LOINC Users` Guide

Transcription

LOINC Users` Guide

Logical Observation Identifiers Names and Codes (LOINC®)
Users' Guide
Edited by:
Clem McDonald, MD, Stan Huff, MD, Jamalynne Deckard, MS, Katy Holck, MPH, Swapna
Abhyankar, MD, Daniel J. Vreeman, PT, DPT
Send questions and comments to:
[email protected]
Copyright © 1995-2016
Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee
All rights reserved.
loinc.org
i
LOINC® Users’ Guide - June 2016
Table of Contents
Table of Contents ......................................................................................................................................... i
Copyright Notice and License .................................................................................................................. vii
Notice of Third Party Content and Copyright Terms ..................................................................................................... xiv
Preface.......................................................................................................................................................... 1
1
2
Introduction ......................................................................................................................................... 5
1.1
Successes ......................................................................................................................................................5
1.2
What is not part of the name ........................................................................................................................6
1.3
Scope of LOINC ..........................................................................................................................................7
1.4
The LOINC Code Identifier .........................................................................................................................7
Major “Parts” of a Test/Observation Name ..................................................................................... 8
2.1
2.1.1
2.1.2
2.1.3
2.1.4
2.1.5
2.1.6
2.2
2.2.1
2.2.2
2.2.3
2.2.4
General naming conventions ........................................................................................................................9
Abbreviations in names of component/analyte ......................................................................................................... 9
General naming rules for the component (analyte) part of the fully specified name. ............................................... 9
Punctuation in analyte names ................................................................................................................................. 11
Case insensitivity .................................................................................................................................................... 11
Roman numerals vs. Arabic numerals .................................................................................................................... 12
Exponents ............................................................................................................................................................... 12
Component/analyte (1st part) ..................................................................................................................... 12
Analyte Name (1st subpart) .................................................................................................................................... 12
Challenge test (2nd subpart) ................................................................................................................................... 13
Adjustments/corrections (3rd subpart) .................................................................................................................... 18
Distinguishing multiple values for any test via the test name (4th subpart) ............................................................ 19
2.3
Kind of Property (also called kind of quantity) (2nd part) ......................................................................... 19
2.4
Time Aspect (Point or moment in time vs. time interval) (3rd part) .......................................................... 26
2.4.1
2.5
2.5.1
2.5.2
Time Aspect Modifier............................................................................................................................................. 27
System (Sample) Type (4th part) ............................................................................................................... 28
Special issues related to XXX as a system.............................................................................................................. 30
Super system (2nd subpart)..................................................................................................................................... 31
2.6
Type of Scale (5th part).............................................................................................................................. 31
2.7
Type of Method (6th part) .......................................................................................................................... 33
2.7.1
2.7.2
2.7.3
2.7.4
2.7.5
2.7.6
2.7.7
2.7.8
DNA/RNA probes/measures................................................................................................................................... 34
PCR assays with non-probe analyte detection methods .......................................................................................... 35
Immune Assays....................................................................................................................................................... 35
Coagulation............................................................................................................................................................. 36
Stains ...................................................................................................................................................................... 36
Substrates used to measure enzyme activity ........................................................................................................... 36
Clinical measures .................................................................................................................................................... 36
Imaging studies ....................................................................................................................................................... 36
2.8
Use of curly braces {} in LOINC names.................................................................................................... 37
2.9
Short Convenient Names............................................................................................................................ 37
2.10
Long Common Names ............................................................................................................................... 37
2.11
Classes........................................................................................................................................................ 38
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3
Special Cases...................................................................................................................................... 38
3.1
3.1.1
3.1.2
3.2
3.2.1
3.2.2
3.3
3.3.1
3.3.2
Value ...................................................................................................................................................................... 39
Variable (Multiple Choice) Approach .................................................................................................................... 39
Blood bank ................................................................................................................................................. 40
Panel reporting:....................................................................................................................................................... 40
Multiple answer reporting:...................................................................................................................................... 40
Immunocompetence studies (flow cytometry) ........................................................................................... 41
Number of cells containing the marker ................................................................................................................... 41
Percent of cells containing the marker .................................................................................................................... 41
3.4
General approach to microbiology results.................................................................................................. 41
3.5
Antimicrobial susceptibilities ..................................................................................................................... 44
3.6
Cell counts.................................................................................................................................................. 44
3.7
Skin tests .................................................................................................................................................... 45
3.8
Toxicology – Drug of Abuse Screening and Confirmation ........................................................................ 45
3.8.1
3.8.2
3.8.3
3.8.4
3.8.5
3.8.6
3.9
3.9.1
3.9.2
3.9.3
3.9.4
3.9.5
3.9.6
3.9.7
4
Findings viewed as variables or as values .................................................................................................. 38
Toxicology drug groups.......................................................................................................................................... 46
Cutoffs .................................................................................................................................................................... 47
Reporting the method used for screen and confirm ................................................................................................ 47
Individual drug/metabolite test results .................................................................................................................... 48
Naming issues ......................................................................................................................................................... 49
Summary ................................................................................................................................................................ 49
Molecular Genetics LOINC Naming ......................................................................................................... 49
Introduction ............................................................................................................................................................ 49
Brief review of molecular genetics terminology ..................................................................................................... 50
Background on molecular genetics testing methods ............................................................................................... 50
General molecular genetics naming rules ............................................................................................................... 51
Infectious diseases .................................................................................................................................................. 53
Genetic conditions .................................................................................................................................................. 54
Identity testing ........................................................................................................................................................ 59
3.10
HLA allele and antigen nomenclature ........................................................................................................ 60
3.11
Allergy Testing .......................................................................................................................................... 60
Clinical observations and measures ................................................................................................ 62
4.1
Introduction ................................................................................................................................................ 62
4.2
Atomic versus molecular (pre-coordinated names) .................................................................................... 64
4.3
Radiology Reports...................................................................................................................................... 65
4.3.1
4.3.2
4.3.3
In-progress changes coming through our collaboration with the RSNA ................................................................. 66
Diagnostic Radiology Reports ................................................................................................................................ 66
Interventional Radiology Reports ........................................................................................................................... 73
5
Tumor registry .................................................................................................................................. 73
6
Claims attachments ........................................................................................................................... 74
7
LOINC Document Ontology ............................................................................................................ 74
7.1
Introduction to the use of LOINC document type codes ............................................................................ 74
7.2
Relationship to other standards .................................................................................................................. 75
7.3
Elements of Document Type codes ............................................................................................................ 75
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7.4
Rules for Creating Clinical Notes from Multiple Components .................................................................. 83
7.4.1
8
Exceptions to Rules for Creating Clinical Notes .................................................................................................... 84
7.5
Document Ontology Content in the LOINC Distribution .......................................................................... 85
7.6
Future Work ............................................................................................................................................... 85
7.7
Proposing new LOINC document terms .................................................................................................... 85
Panels (Batteries) .............................................................................................................................. 85
8.1
Goals .......................................................................................................................................................... 86
8.2
Types of results found in panels ................................................................................................................. 86
8.2.1
8.2.2
8.2.3
8.2.4
8.3
Primary measurements or observations .................................................................................................................. 86
Derived observations .............................................................................................................................................. 87
Ask at order entry (AOE) questions and other associated observations.................................................................. 87
Impressions, interpretations, and comments ........................................................................................................... 87
LOINC rules for panel names .................................................................................................................... 87
8.3.1
8.3.2
8.3.3
8.3.4
8.4
Component ............................................................................................................................................................. 87
Property and Scale .................................................................................................................................................. 88
Time Aspect and System ........................................................................................................................................ 88
Examples of LOINC Panel names .......................................................................................................................... 88
Representing conditionality........................................................................................................................ 88
8.4.1
8.5
Lupus anticoagulant (LA) testing as an example of complex conditionality .......................................................... 90
Approach to creating and defining distinct panels in LOINC .................................................................... 91
8.5.1
8.5.2
8.5.3
9
General approach .................................................................................................................................................... 91
Preference for methodless panel definitions ........................................................................................................... 92
Special cases where enumeration of child elements is not practical ....................................................................... 93
Evolving principles for naming collections ..................................................................................... 93
9.1
Goals and general approach ....................................................................................................................... 93
9.2
Collections as orders and observations ...................................................................................................... 94
9.3
LOINC SCALE for collections .................................................................................................................. 94
9.4
Examples of proposed changes according to new policy ........................................................................... 94
10
Additional Content in the LOINC Distribution ......................................................................... 95
10.1
LOINC Answers and Answer Lists ............................................................................................................ 95
10.1.1
Null flavors in LOINC answer lists ................................................................................................................... 96
10.2
LOINC Parts and Part Hierarchies ............................................................................................................. 96
10.3
Use of the ORDER_OBS field for LOINC terms ...................................................................................... 96
11
Standardized Assessment Measures ............................................................................................ 97
11.1
Introduction ................................................................................................................................................ 97
11.2
Consolidated Health Informatics endorsement .......................................................................................... 98
11.3
LOINC Representation............................................................................................................................... 98
11.3.1
11.3.2
11.3.3
11.3.4
11.3.5
11.3.6
Naming rules and conventions for names of collection terms (e.g. a panel, survey instrument) ........................ 98
Attributes of the LOINC terms for individual questions or variables ................................................................ 98
Structured answer lists ....................................................................................................................................... 99
Attributes of items that vary depending on the parent collection ....................................................................... 99
Choosing the “display text” for a question or variable....................................................................................... 99
Type of Method (6th part) for a question or variable ....................................................................................... 100
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11.4
12
Assessment Content in the LOINC Distribution ...................................................................................... 100
Editorial Policies and Procedures .............................................................................................. 101
12.1
Concept orientation and LOINC name changes ....................................................................................... 101
12.2
Classification of LOINC term status ........................................................................................................ 101
12.3
Concept persistence and term deprecation ............................................................................................... 103
13
Recommendations for Best Practices in Using and Mapping to LOINC ............................... 103
13.1
Business rules for users mapping their local panels to LOINC panels ..................................................... 103
13.1.1
13.1.2
13.1.3
13.1.4
13.1.5
13.1.6
13.1.7
13.1.8
13.1.9
13.2
Must contain all of the required elements ........................................................................................................ 103
No extra primary measurements ...................................................................................................................... 103
Optional elements are optional ........................................................................................................................ 103
Substitutions related to Method ....................................................................................................................... 103
Substitutions for mass versus substance Properties.......................................................................................... 104
No substitutions of quantitative for qualitative (and vice versa) ...................................................................... 104
Pay attention to reflex components .................................................................................................................. 104
Special case of differential counts (including conventions for not reporting zero counts) ............................... 105
Panels with only narrative definitions of the elements they should contain ..................................................... 105
Examples of applying the business rules for users mapping their local panels to LOINC panels............ 105
13.2.1
13.2.2
13.2.3
Comparison Panel: Varicella zoster virus IgG and IgM panel - Serum (LOINC # 45063-5)........................... 105
Comparison Panel: Creatine kinase panel - Serum or Plasma (LOINC # 24335-2) ......................................... 105
Comparison Panel: Drugs of abuse 5 panel - Urine by Screen method (LOINC # 65750-2) ........................... 106
13.3
Querying LOINC and creating intensional value set definitions based on LOINC database structure ... 107
13.4
LOINC term names in HL7 messages ...................................................................................................... 107
13.5
Updating to new versions of LOINC ....................................................................................................... 107
13.6
Using a URI to identify LOINC concepts as resources in RDF ............................................................... 108
Appendix A - LOINC Database Structure ........................................................................................... 109
Appendix B - Classes .............................................................................................................................. 113
Appendix C - Calculating Mod 10 Check Digits .................................................................................. 121
Appendix D - Procedure for Submitting Additions/Changes to LOINC ........................................... 122
Appendix E - Examples for LOINC Property Matching .................................................................... 125
Appendix F – Example Acronyms used in LOINC .............................................................................. 129
Appendix G – LOINC Technical Briefs ................................................................................................ 132
D-DIMER .............................................................................................................................................................. 133
Cockcroft-Gault formula for estimating creatinine clearance, Schwartz equation for Glomerular Filtration Rate
and MDRD formulae ............................................................................................................................................. 137
Inducible Clindamycin Resistance in Staphylococcus and Streptococcus ............................................................ 141
The KIR Gene Family ........................................................................................................................................... 142
Oxygen Saturation and LOINC® .......................................................................................................................... 143
Nomenclature of Salmonella Species, Subspecies, and Serovars .......................................................................... 146
v
Segmented Neutrophils Versus Polymorphonuclear WBC ................................................................................... 148
Vitamin D .............................................................................................................................................................. 149
Free Thyroxine Index Variants.............................................................................................................................. 152
Appendix H - LOINC Committee Members ........................................................................................ 154
RadLex-LOINC Radiology Playbook User Guide .......................................................................... Annex
Tables
Table 1: Hierarchical Structure of Fully Specified Analyte Names ........................................................................8
Table 2: Example Component Abbreviations ...........................................................................................................9
Table 3: Example Case Specifying Conventions ..................................................................................................... 11
Table 4: Example Time Delay Post Challenge ........................................................................................................ 14
Table 5: Example Challenge Subparts..................................................................................................................... 15
Table 6: Example Route Abbreviations for Challenge Part .................................................................................. 15
Table 7: Example Nature of Challenge .................................................................................................................... 16
Table 8: Example LOINC properties....................................................................................................................... 21
Table 9: Example Duration Categories ................................................................................................................... 27
Table 10: Time Aspect Modifier Codes ................................................................................................................... 27
Table 11: Example Laboratory System/Sample Types .......................................................................................... 29
Table 12: Type of Scale ............................................................................................................................................. 31
Table 13: Laboratory Method Type Abbreviations................................................................................................ 33
Table 14a: Examples of specific methods that would be classed as target amplified DNA/RNA ....................... 34
Table 14b: Examples of specific methods that would be defined in LOINC as signal amplification methods .. 35
Table 15: Example Culture Results ......................................................................................................................... 43
Table 16: Drug Susceptibility Methods ................................................................................................................... 44
Table 17: Drug of Abuse Methods ........................................................................................................................... 45
Table 18: Four types of nomenclatures for identifying the location of a genetic defect ...................................... 51
Table 19: List of single letter amino acid codes ...................................................................................................... 52
Table 20: Example subjects covered in clinical LOINC ......................................................................................... 63
Table 21: Examples of Pre-Coordinated Names ..................................................................................................... 65
Table 22: Example Clinical Notes ............................................................................................................................ 74
Table 23. Document Ontology LOINC Naming Rules ........................................................................................... 83
Table 24. Example Document Ontology LOINC Codes ......................................................................................... 84
Table 25. LOINC Code Exceptions to Creating a General Clinical Document Code .......................................... 84
Table 26. LOINC Codes with only a Kind of Document ........................................................................................ 85
Table 27: Examples of LOINC Panel Names (Order Set Names) ......................................................................... 88
Table 28: Example Order Sets.................................................................................................................................. 89
Table 29: Options for Term Conditionality within Panels ..................................................................................... 89
Table 30: Example of Proposed Changes ................................................................................................................ 94
Table 31a: LOINC Table Structure ....................................................................................................................... 109
Table 31b: MAP_TO Table Structure ................................................................................................................... 112
Table 31c: Source Organization Table Structure ................................................................................................. 112
Table 32a: Clinical Term Classes ........................................................................................................................... 113
Table 32b: Laboratory Term Classes .................................................................................................................... 116
Table 32c: Attachment Term Classes .................................................................................................................... 117
Table 32d: Survey Term Classes ............................................................................................................................ 118
Table 33: Example Acronyms used in LOINC...................................................................................................... 129
vi
Copyright Notice and License
The LOINC® codes, LOINC® table (regardless of format), LOINC® Release Notes, LOINC®
Changes File, and LOINC® Users' Guide are copyright © 1995-2016, Regenstrief Institute, Inc.
and the Logical Observation Identifiers Names and Codes (LOINC) Committee. All rights
reserved.
The RELMA® program, RELMA® database and associated search index files (subject to the
copyright above with respect to the LOINC® codes and LOINC® table included therein),
RELMA® Community Mapping Feature Database, RELMA® Release Notes, and RELMA®
Users' Manual are copyright © 1995-2016, Regenstrief Institute, Inc. All rights reserved.
The LOINC® panels and forms file; LOINC® document ontology file; and the LOINC®
hierarchies, LOINC® linguistic variants files, LOINC/RSNA Radiology Playbook, and
LOINC/IEEE Medical Device Code Mapping Table (all subject to the copyright above with
respect to the LOINC® codes and LOINC® table to the extent included therein), are copyright ©
1995-2016, Regenstrief Institute, Inc. All rights reserved.
LOINC® and RELMA® are registered United States trademarks of Regenstrief Institute, Inc.
Permission is hereby granted in perpetuity, without payment of license fees or royalties, to use,
copy, or distribute the RELMA® program, RELMA® Users' Manual, RELMA® Release Notes,
RELMA® database and associated search index files, LOINC® codes, LOINC® Users' Guide,
LOINC® table (in all formats in which it is distributed by Regenstrief Institute, Inc. and the
LOINC Committee), LOINC® Release Notes, LOINC® Changes File, LOINC® panels and
forms file, LOINC® document ontology file, LOINC® hierarchies file, LOINC® linguistic
variants file, LOINC/RSNA Radiology Playbook, and LOINC/IEEE Medical Device Code
Mapping Table (collectively, the "Licensed Materials") for any commercial or non-commercial
purpose, subject to the following terms and conditions:
1. To prevent the dilution of the purpose of the LOINC codes and LOINC table of providing
a definitive standard for identifying clinical information in electronic reports, users shall
not use any of the Licensed Materials for the purpose of developing or promulgating a
different standard for identifying patient observations, such as laboratory test results;
other diagnostic service test results; clinical observations and measurements; reports
produced by clinicians and diagnostic services about patients; panels, forms, and
collections that define aggregations of these observations; and orders for these entities in
electronic reports and messages.
2. If the user elects to use the RELMA program, users receive the full RELMA database and
associated search index files with the RELMA program, including the LOINC table and
other database tables comprising the RELMA database. In addition to its use with the
RELMA program, users may use the LOINC table by itself and may modify the LOINC
table as permitted herein. Users may not use or modify the other database tables from the
RELMA database or the associated search index files except in conjunction with their
authorized use of the RELMA program, unless prior written permission is granted by the
vii
Regenstrief Institute, Inc. To request written permission, please contact
[email protected]. The RELMA program also provides access to certain internetbased content copyrighted by Regenstrief Institute, Inc. No additional permission to
modify or distribute this internet-based content is granted through the user’s use of the
RELMA program.
3. The RELMA program also includes the RELMA Community Mappings feature and
access to the RELMA Community Mappings feature database. The accuracy and
completeness of the information in the RELMA Community Mappings feature is not
verified by Regenstrief Institute, Inc. or the LOINC Committee. Access to the RELMA
Community Mappings feature is enabled by a user authentication from the RELMA login
screen. If a user wishes to opt out of the RELMA Community Mappings feature, they can
simply use RELMA without logging in.
1. By using the RELMA Community Mappings feature, users agree as follows:
i.
Users may not copy, distribute, or share access to the information
provided by the RELMA Community Mappings feature.
ii. Users accept the risk of using the information provided by the RELMA
Community Mappings feature, recognize that such information is
submitted by other users, and understand that neither Regenstrief Institute,
Inc. nor the LOINC Committee are liable for the information provided by
the RELMA Community Mappings feature.
iii. Regenstrief Institute, Inc. may contact users regarding:
1. Use of the RELMA Community Mappings feature;
2. Submission requests for additional information; and
3. Any mapping submissions that the user makes to the RELMA
Community Mappings feature database;
iv.
Others may contact user about submissions made to the RELMA
Community Mappings feature database;
v.
User will make reasonable efforts to submit user’s mappings back to the
RELMA Community Mappings feature database, which may contain the
following information (as applicable):
1. Local battery/panel/test code
2. Local battery/panel/test name/description
3. Units of Measure
4. LOINC code to which it is mapped
5. Date of mapping
6. Language of test names
7. Version of LOINC used to do the mapping
8. Contact information;
vi.
If a user submits mappings on behalf of an organization, the user
represents that the user has the authority to submit the mappings and to
agree to these terms on behalf of user’s organization.
vii.
If a user submits mappings back to the RELMA Community Mappings
feature database, then the user hereby grants, on behalf of themselves and
user’s organization, Regenstrief Institute, Inc. a non-exclusive license
without payment or fees to submitted mappings in perpetuity for purposes
viii
4.
5.
6.
7.
8.
related to LOINC, RELMA, and Regenstrief Institute Inc.’s mission,
including, but not limited to:
1. Modifying the information;
2. Making information publicly available;
3. Performing aggregate analysis;
4. Conducting and publishing research that does not identify user or
user’s organization by name;
5. Developing and enhancing LOINC and associated software tools.
Users shall not change the meaning of any of the LOINC codes. Users shall not change
the name of, or any contents of, any fields in the LOINC table. Users may add new fields
to the LOINC table to attach additional information to existing LOINC records. Users
shall not change the content or structure of the LOINC document ontology file or the
LOINC panels and forms from the LOINC panels and forms file, but may notify the
Regenstrief Institute, Inc. of any potential inconsistencies or corrections needed by
contacting [email protected].
Users shall not use the LOINC parts or LOINC part hierarchies in any manner except as
they are presented in the Licensed Materials (and/or in other formats of distribution
approved by Regenstrief Institute, Inc.) to organize or be constituents of LOINC terms.
LOINC parts and LOINC part hierarchies shall neither be used as a “standalone”
terminology nor apart from LOINC terms. User understands that LOINC parts and
LOINC part hierarchies are subject to change, addition, modification, or deletion, and are
not strictly managed under the same policies as LOINC terms.
A user may delete records from the LOINC table to deal with the user's local
requirements. A user also may add new records to the LOINC table to deal with the users'
local requirements, provided that if new records are added, any new entry in the
LOINC_NUM field of such new records must contain a leading alphabetic "X" so that
the new codes and records cannot be confused with existing LOINC codes or new
LOINC codes as they are defined in later releases of the LOINC table. Records deleted or
added by users to deal with local requirements are not reflected in the official LOINC
table maintained by the Regenstrief Institute, Inc. and the LOINC Committee. Users must
also make reasonable efforts to submit requests to LOINC for new records to cover
observations that are not found in the LOINC table in order to minimize the need for Xcodes.
LOINC codes and other information from the LOINC table may be used in electronic
messages for laboratory test results and clinical observations such as HL7 ORU
messages, without the need to include this Copyright Notice and License or a reference
thereto in the message (and without the need to include all fields required by Section 9
hereof). When the LOINC code (from the LOINC_NUM field) is included in the
message, users are encouraged, but not required, to include the corresponding LOINC
short name (from the SHORTNAME field) or the LOINC long common name (from the
LONG_COMMON_NAME field) in the message if the message provides a place for a
text name representation of the code.
Users may make and distribute an unlimited number of copies of the Licensed Materials.
Each copy thereof must include this Copyright Notice and License, and must include the
appropriate version number of the Licensed Materials if the Licensed Materials have a
version number, or the release date if the Licensed Materials do not have a version
ix
number. This Copyright Notice and License must appear on every printed copy of the
LOINC table. Where the Licensed Materials are distributed on a fixed storage medium
(such as CD-ROM), a printed copy of this Copyright Notice and License must be
included on or with the storage medium, and a text file containing this information also
must be stored on the storage medium in a file called "license.txt". Where the Licensed
Materials are distributed via the Internet, this Copyright Notice and License must be
accessible on the same Internet page from which the Licensed Materials are available for
download. This Copyright Notice and License must appear verbatim on every electronic
or printed copy of the RELMA Users' Manual and the LOINC Users' Guide. The
RELMA Users' Manual and the LOINC Users' Guide may not be modified, nor may
derivative works of the RELMA Users' Manual or LOINC Users' Guide be created,
without the prior written permission of the Regenstrief Institute, Inc. To request written
permission, please contact [email protected]. The Regenstrief Institute retains the
right to approve any modification to, or derivative work of, the RELMA Users' Manual
or the LOINC Users' Guide.
9. Subject to Section 1 and the other restrictions hereof, users may incorporate portions of
the LOINC table, LOINC panels and forms file, LOINC document ontology file, LOINC
hierarchies file, LOINC linguistic variants file, LOINC/RSNA Radiology Playbook, and
LOINC/IEEE Medical Device Code Mapping Table into another master term dictionary
(e.g. laboratory test definition database), or software program for distribution outside of
the user's corporation or organization, provided that any such master term dictionary or
software program includes the following fields reproduced in their entirety from the
LOINC table: LOINC_NUM, COMPONENT, PROPERTY, TIME_ASPCT, SYSTEM,
SCALE_TYP, METHOD_TYP, STATUS, and SHORTNAME. Users are also required
to either: (1) include the EXTERNAL_COPYRIGHT_NOTICE or (2) delete the rows
that include third party copyrighted content (e.g., third party survey instruments and
answers). If third party content is included, users are required to comply with any such
third party copyright license terms. Users are encouraged, but not required, to also
include the RelatedNames2 and the LONG_COMMON_NAME in any such database.
Further description of these fields is provided in Appendix A of the LOINC Users' Guide.
Every copy of the LOINC table, LOINC panels and forms file, LOINC document
ontology file, LOINC hierarchies file, LOINC linguistic variants file, LOINC/RSNA
Radiology Playbook, and/or LOINC/IEEE Medical Device Code Mapping Table
incorporated into or distributed in conjunction with another database or software program
must include the following notice:
"This product includes all or a portion of the LOINC® table, LOINC panels and
forms file, LOINC document ontology file, LOINC hierarchies file, LOINC
linguistic variants file, LOINC/RSNA Radiology Playbook, and/or LOINC/IEEE
Medical Device Code Mapping Table or is derived from one or more of the
foregoing, subject to a license from Regenstrief Institute, Inc. Your use of the
LOINC table, LOINC codes, LOINC panels and forms file, LOINC document
ontology file, LOINC hierarchies file, LOINC linguistic variants file,
LOINC/RSNA Radiology Playbook, and LOINC/IEEE Medical Device Code
Mapping Table also is subject to this license, a copy of which is available
at http://loinc.org/terms-of-use. The current complete LOINC table, LOINC Users'
x
Guide, LOINC panels and forms file, LOINC document ontology file, LOINC
hierarchies file, LOINC linguistic variants file, LOINC/RSNA Radiology
Playbook, and LOINC/IEEE Medical Device Code Mapping Table are available
for download at http://loinc.org. The LOINC table and LOINC codes are copyright
© 1995-2016, Regenstrief Institute, Inc. and the Logical Observation Identifiers
Names and Codes (LOINC) Committee. The LOINC panels and forms file, LOINC
document ontology file, LOINC hierarchies file, LOINC linguistic variants file,
and LOINC/RSNA Radiology Playbook, and LOINC/IEEE Medical Device Code
Mapping Table are copyright © 1995-2016, Regenstrief Institute, Inc. All rights
reserved. THE LOINC TABLE (IN ALL FORMATS), LOINC PANELS AND
FORMS FILE, LOINC DOCUMENT ONTOLOGY FILE, LOINC
HIERARCHIES FILES, LOINC LINGUISTIC VARIANTS FILE, LOINC/RSNA
RADIOLOGY PLAYBOOK, AND LOINC/IEEE MEDICAL DEVICE CODE
MAPPING TABLE ARE PROVIDED "AS IS." ANY EXPRESS OR IMPLIED
WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE. LOINC® is a registered United States trademark of
Regenstrief Institute, Inc. A small portion of the LOINC table may include content
(e.g., survey instruments) that is subject to copyrights owned by third parties. Such
content has been mapped to LOINC terms under applicable copyright and terms of
use. Notice of such third party copyright and license terms would need to be
included if such content is included."
If the master term dictionary or software program containing the LOINC table, LOINC
panels and forms file, LOINC document ontology file, LOINC hierarchies file, LOINC
linguistic variants file, LOINC/RSNA Radiology Playbook, and/or LOINC/IEEE Medical
Device Code Mapping Table is distributed with a printed license, this statement must
appear in the printed license. Where the master term dictionary or software program
containing the LOINC table, LOINC panels and forms file, LOINC document ontology
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xi
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xiv
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xv
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xvi
Preface
LOINC provides a set of universal names and ID codes for identifying laboratory and clinical test
results.1,2 LOINC facilitates the exchange and pooling of results, such as blood hemoglobin, serum
potassium, or vital signs, for clinical care, outcomes management, and research. Currently, many
laboratories use ASTM 12383 or its sister standard, HL74, to send laboratory results electronically from
production laboratories to clinical care systems in hospitals. Most laboratories identify tests in HL7
messages by means of their internal (and idiosyncratic) code values. Receiving medical information
systems cannot fully “understand” the results they receive unless they either adopt the producer's
laboratory codes (which is impossible if information system receives results from multiple source
laboratories, e.g., the hospital lab, the local commercial lab, and a nursing home lab), or invest in the
work to map each laboratory's coding system to their internal code system.5
If medical information producers who wish to communicate with each other adopt LOINC codes to
identify their results in data transmissions, this problem would disappear. The receiving system with
LOINC codes in its master vocabulary file would be able to understand and properly file HL7 results
messages that identified clinical observations via LOINC codes. Similarly, if test and observation codes
were reported test with the LOINC codes, government agencies would be able to pool results for tests
from many sites for research management and public health purpose. The LOINC codes (and names) for
test observations should be of interest to hospitals, clinical laboratories, doctors' offices, state health
departments, governmental health care providers, third-party payers, and organizations responsible for
quality assurance and utilization review.
The LOINC codes are not intended to transmit all possible information about a test or observation. They
are only intended to identify the test result or clinical observation. Other fields in the message can
transmit the identity of the source laboratory and special details about the sample. (For instance, the result
code may identify a blood culture, but the message source code can be more specific and identify the
sample as pump blood.) The level of detail in the LOINC definitions was intended to distinguish tests that
are usually distinguished as separate test results within the master file of existing laboratory systems.
Indeed, at the outset, we used the master files from seven U.S. laboratories to shape this effort, and
requests from commercial labs and hospitals continue to shape the content of the LOINC effort.
Each LOINC record corresponds to a single test result or panel. The record includes fields for specifying:
1. Component (analyte) - e.g., potassium, hemoglobin, hepatitis C antigen.
2. Property measured - e.g., a mass concentration, enzyme activity (catalytic rate).
3. Timing - i.e., whether the measurement is an observation at a moment of time, or an observation
integrated over an extended duration of time - e.g., 24-hour urine.
4. The type of sample - e.g., urine, blood.
5. The type of scale - e.g., whether the measurement is quantitative (a true measurement) ordinal (a
1
Forrey AW, McDonald CJ, DeMoor G, Huff, SM, Leavelle D, Leland D, Fiers T, Charles L, Stalling F, Tullis A, et. al. The logical
observation identifier names and codes (LOINC) database: A public use set of codes and names for electronic reporting of clinical laboratory
results. Clinical Chemistry 1996;42:81-90.
2
McDonald CJ, Huff SM, Suico JG, Hill G, Leavelle D, Aller R, Forrey A, Mercer K, DeMoor G, Hook J, Williams W, Case J,
Maloney P. LOINC, a universal standard for identifying laboratory observations: A 5-Year update. Clinical Chemistry 2003;49:624-633.
3
ASTM E1238-94. Standard Specification for Transferring Clinical Observations Between Independent Computer
Systems. Philadelphia: American Society for Testing Materials; 1994.
4
Health Level Seven. An application protocol for electronic data exchange in healthcare environments. Version 2.3
Ann Arbor, MI: Health Level Seven, Inc.; 1997.
5
McDonald CJ, Park BH, Blevins L. Grocers, physicians, and electronic data processing. AMA Continuing Medical Education
Newsletter 1983;1:5-8.
1
ranked set of options), nominal (e.g., E. coli; Staphylococcus aureus), or narrative (e.g., dictation
results from x-rays).
6. Where relevant, the method used to produce the result or other observation.
It also contains information about the amount, route, and timing of physiologic or pharmacologic
challenges. For example, a glucose tolerance test could be expressed in LOINC as Glucose^1H post 100 g
glucose PO. LOINC does not usually include the method in the name for chemistry tests, where tests are
more often standardized to normalized methods; they do include methods for most serological tests and
coagulation studies. This same principle is usually reflected in the master files of existing laboratories. Of
course, the method can always be reported as a separate item of information in a result message,
regardless of whether it is part of the test name.
We used many sources for constructing the database, including the Silver Book from the International
Union of Pure and Applied Chemistry (IUPAC) and the International Federation of Clinical Chemistry
(IFCC), 6 textbooks of clinical pathology (e.g., Henry7 and Tietz8), the expertise and work of the LOINC
members, and EUCLIDES. We have also reviewed the master test files of seven sources (Indiana
University/Regenstrief, University of Utah, Association of Regional and University Pathologists (ARUP),
Mayo Medical Laboratories, LDS Hospital in Salt Lake City, the Department of Veterans Affairs, Quest
Diagnostics, and University of Washington). This has been an empirical effort. Our goal is to provide
codes that correspond to the concepts in real world laboratories’ and clinical departments’ master files.
LOINC includes fields for each of the six parts of the name. In addition, it also contains short names (as
of the August 2002 version for laboratory tests), related words, synonyms, and comments for all
observations. Related words (synonyms) are included to facilitate searches for individual laboratory test
and clinical observation results.
We have defined fields in LOINC for a number of data elements, e.g., typical units, sample normal
ranges, but most of those fields are only partially populated. In a few cases, we have suggested standard
answer lists for tests whose results are usually reported as codes. LOINC is an ongoing project. We have
established guidelines for users who wish to request additions and changes, which are detailed in
Appendix D.
For some kind of tests and observations, the database provides several ways to report values. For
example, blood cell antigens might be presented as a “panel” with separate “tests” which report each
possible antigen as present or absent if the test is to establish paternity; for cross matching, the result
would be reported as a list of antigens found. We try to provide for both methods of reporting in LOINC
by including codes for both types of test identifiers.
Laboratories and managers of medical records systems should record the LOINC codes as attributes of
their existing test/observation master files. They should also use the LOINC codes and names in the
OBSERVATION ID field (OBX-3) of the ASTM and HL7 OBX segment and the corresponding CEN
TC251 and DICOM messages to identify laboratory results.
The overall organization of LOINC is divided first into four categories, “lab”, “clinical”, “attachments”
and “surveys”. (This split is recorded in CLASSTYPE field of the LOINC Table.) The laboratory portion
is further divided into the usual categories of chemistry, hematology, serology, microbiology (which
6
International Union of Pure and Applied Chemistry/International Federation of Clinical Chemistry. The Silver Book: Compendium of
terminology and nomenclature of properties in clinical laboratory sciences. Oxford: Blackwell Scientific Publishers; 1995.
7
Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Philadelphia:W.B. Saunders; 1994.
8
Burtis CA, Ashwood ER (editors). Tietz Textbook of Clinical Chemistry, 2nd ed. Philadelphia:W.B. Saunders; 1994.
2
includes parasitology and virology), and toxicology. We have separated antibiotic susceptibilities into
their own category. The clinical portion of LOINC contains entries for vital signs, hemodynamics,
intake/output, EKG, obstetric ultrasound, cardiac echo, urologic imaging, gastroendoscopic procedures,
pulmonary ventilator management, and other clinical observations. Appendix B lists these classes in more
detail. There is nothing sacred about these categories, and you are free to sort the database by whatever
class is convenient for your application.
The Regenstrief Institute maintains LOINC and makes it available in a number of file formats. LOINC
and the related files (such as this document) are copyrighted to assure that multiple variants of the
standard do not emerge. Having many variants would defeat the purpose of a universal identifier for test
results. LOINC is made available at no cost worldwide under the license at http://loinc.org/terms-of-use.
The LOINC Table, supporting documentation and supplemental files, and the RELMA® mapping
program are all made available by the Regenstrief Institute on the LOINC website (http://loinc.org).
The primary files in the LOINC distribution are listed below.
LOINC Table – Microsoft Access Format
All the fields of the LOINC Table available in a Microsoft Access™ database format.
LOINC Table – Text Format (Comma Delimited)
All the fields of the LOINC Table with each record on a separate line (terminated by CR/LF), and
each field delimited by a comma character. The data files in this package are provided in the
Comma Separated Value (CSV) format according to RFC 4180 and encoded with UTF-8. This
package also contains basic scripts for loading the data into some popular databases (Oracle and
MySQL for now).
LOINC Users' Guide (this document)
The LOINC Users’ Guide is the definitive document about LOINC and is available as a PDF file.
It explains the structure of the table, its rationale, and the rules we used for naming test results.
RELMA
The Regenstrief Institute also produces a Windows-based mapping utility called the Regenstrief
LOINC Mapping Assistant (RELMA®) to facilitate searches through LOINC and to assist efforts
to map local codes to LOINC codes. This program is also available for free use.
RELMA Users' Manual
The definitive guide to using the RELMA program.
All of the above files are available from the LOINC website at http://loinc.org.
Additionally, Regenstrief provides a web-based search application available at http://search.loinc.org that
can be used to search the latest version of LOINC right from your Internet browser.
We welcome corrections or extensions to the database. We are not interested in adding terms that might
be needed in some future situation but we are interested in adding test observations that are actively being
reported today. Appendix D provides instructions for submitting new terms.
Clem McDonald
Chairman, LOINC Committee
Chairman, Laboratory LOINC Committee
Stan Huff
Co-Chairman, LOINC Committee
Chairman, Clinical LOINC Committee
3
Acknowledgments
Over the years, LOINC has been supported financially by many organizations and individuals. We're
thankful for the generous support from:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Regenstrief Institute
Regenstrief Foundation
National Library of Medicine (Contracts NO1-LM-4-3510, N01-LM-6-3546, N01-LM-9-3517,
and HHSN276200800006C, HHSN276201400138P, HHSN276201400239P)
American Physical Therapy Association
bioMérieux
Indiana Clinical and Translational Sciences Institute
California Healthcare Foundation
Radiological Society of North America through the National Institute of Biomedical Imaging and
Bioengineering
AHIMA Foundation (Contract FORE-ASPE-2007-5)
RTI International (Contract 0-312-0209853)
John A. Hartford Foundation of New York
Agency for Health Care Policy and Research (Grants HS 08750 and HS 07719-03)
Centers for Disease Control and Prevention (Grant and Contracts R13/CCR517099 and
H75/CCH520501)
Members of the LOINC Community who have made donations or became Premium Members
This work was initiated by and performed under the auspices of the Regenstrief Institute.
We remain grateful to the late Dr. Henrik Olesen for his very helpful comments and insights about
laboratory test coding. Dr. Olesen served as chair of the Commission on Nomenclature for Properties and
Units (1989) and member of the joint IUPAC-IFCC Commission on Nomenclature, Properties and Units
(1988-1997).
4
1
Introduction
The goal of the LOINC project is to create universal identifiers (names and codes) used in the context of
existing ASTM E1238, HL7, CEN TC251, and DICOM observation report messages employed in the
various sub-domains of healthcare informatics such as Clinical Laboratory Information Management
Systems and Computer-Based Patient Record Systems.9, 10 Specifically, the identifiers can be used as the
coded value of the “Observation Identifier” field (# 3) of the OBX segment of an ORU HL7 (HL7 version
2.x or ASTM 1238-9410) messages, or in a corresponding field in future versions of these HL7 and
DICOM standards. LOINC codes, identified in HL7 as code system “LN”, provide “universal” identifiers.
When used in the context of messaging standards, LOINC codes allow the exchange of clinical laboratory
data between heterogeneous computing environments.
To facilitate this process, each identifier requires a fully specified name created in a standard way. This
way, users can create long names for their tests that can be linked to the universal test identifier using
semi-automated methods.
We focused our initial effort on creating names for results of reportable tests or clinical measurements
rather than request-able batteries, because the issues involved in naming results of tests are less complex
than those involved in naming the batteries. However, we have also defined codes for some order panels.
It is important to note that LOINC codes for single tests, reports, and observations are equally suitable for
the ordered item in an order record or message, or as the result identifier in a result message.
The LOINC database is a “universal” master file of standard “test” names and codes that will cover most
of the entries in these files of operational laboratory systems, so that the terms in these operational master
files could be mapped directly to universal codes and names. The names we create correspond most
closely to the “long test descriptions” seen in test master files. The LOINC names are “fully specified”
names. That is, if a person wanted to map her local test dictionary to the LOINC codes, all the
information needed to map a local test name to one of the fully specified names should be present in the
LOINC name.
We aim to achieve a level of detail in the definition of a test that will map one-to-one to the separately
reported observations on a clinical laboratory report. If a test has its own column on a clinical report, or
has a reference range that is significantly different from other tests, or has a different clinical meaning
than other related tests, it will usually be assigned a separate LOINC code and name. We deliver these
fully specified names, their codes, and their related names as a database in which each line corresponds to
a unique test measurement.
1.1 Successes
The LOINC codes have been greeted enthusiastically since they were released to the Internet in April of
1996. Today, LOINC has been adopted widely. It is used in settings of all kinds, from clinical institutions
to health systems, IT vendors, research projects, government agencies, and international e-Health projects
spanning many countries. There are now more than 44,300 users in 172 different countries. LOINC
adoption worldwide has steadily accelerated. We are now adding more than 600 new users per month.
Many countries have adopted LOINC as a national standard, including Australia, Brazil, Canada, Cyprus,
9
10
McDonald CJ, Tierney WM. Computer-stored medical records. JAMA 1988;259:3433-40.
Dick AS, Steen EB (editors). The computer based patient record. Washington DC: National Academy Press; 1991.
5
Estonia, France, Germany, Mexico, Mongolia, the Netherlands, Rwanda, Thailand, Turkey, and the
United States. There are large-scale health information exchanges using LOINC in Hong Kong, Italy, the
Philippines, Spain, Singapore, and Korea as well. The LOINC content and associated documentation have
been translated into many languages. We have developed a mechanism to make the process more efficient
for our translators by using the atomic parts that a term is composed of. Both RELMA and the online
LOINC search application (http://search.loinc.org) now have multilingual searching capabilities. We have
described how our approach to translations supports international adoption,11, and we highlight the work
of our international colleagues in a special section on the LOINC website at http://loinc.org/international.
We provide a voluntary directory of organizations that have adopted LOINC on our website
(http://loinc.org/adopters) and give news updates on domestic and international adoption at our meetings.
1.2 What is not part of the name
Certain parameters and descriptions pertaining to test performance are specifically excluded from the
fully specified test name. These parameters will typically be reported in separate fields (attributes) of a
test/observation report message, not as part of the observation name. Attributes that we explicitly exclude
from the fully specified name are:
•
•
•
•
•
•
the instrument used in testing
fine details about the sample or the site of collection such as “right antecubital fossa”
the priority of the testing, e.g., whether stat or routine
who verified the result
the size of the sample collected
the place of testing (e.g., home, bedside, clinical lab)
In the case of laboratory tests, the name does include information that identifies the type of sample (or
specimen). However, the “sample” part of the name is not meant to carry all possible information about
the sample, but only enough to indicate significant differences in the result and to reflect current usage in
test names. For example, laboratories usually define urine sodium, sweat sodium, and serum sodium as
different tests because each of these has a different normal range. But laboratories do not define different
tests to distinguish the concentration of arterial serum sodium from venous serum sodium, though the lab
may report that the sample was venous or arterial in another part of the report. We are guided by the
pragmatics of conventional usage. If laboratories define separate tests for the same measurements done on
different specimens (this usually implies a well-defined normal range difference), we will define different
“result-able” tests in our dictionary. If they do not, we will not.
The extent to which we include methods as part of the name is also guided by pragmatics. We distinguish
tests/observations by the type of method used to produce the results only if a given type of method has an
important effect on the interpretation of the result. This is a complex subject and it is difficult to fully
describe our rationale in this guide. Where laboratories do not tend to include the method in the name
(e.g., most of chemistry) we do not include the method in the name. Where they tend to (e.g., in
immunochemistry) we do. For some tests, this can be justified by the standardization of methods to
produce “equivalent” results, and sometimes by the many variables (method, reagent) that one could
never hope to represent fully in a single name. However, even when we do distinguish these cases, we
distinguish by type of method, not the most detailed possible method distinction. (See section 2.7, Type
of Method, for more details.)
11
Vreeman DJ, Chiaravalloti MT, Hook J, McDonald CJ. Enabling international adoption of LOINC through translation. J Biomed
Inform. 2012 Aug;45(4):667-73. doi: 10.1016/j.jbi.2012.01.005. Epub 2012 Jan 21. PubMed PMID: 22285984;
6
The College of American Pathologists produces statistical summaries of the results for measurements of
standard samples broken down by laboratory and by instrument or procedure. (These are called CAP
surveys.) We considered using this CAP survey data to decide empirically when test names should be
distinguished by method, but decided this was not feasible because many of the apparent differences in
method obtained with the standard samples were artifacts of the sample matrix and did not apply to serum
specimens. In addition, the variation among laboratories was often of the same magnitude as the variation
among methods within laboratories for the same method.
We do not mean to underrate the importance of method differences. The result message will still include
information about the normal range for that particular test, the source laboratory and, if the laboratory
wishes, specific information about the method. However, such information is reported in separate fields in
the HL7 message (e.g., OBX-17 can carry very detailed method information). It is not embedded in the
names of the test.
1.3 Scope of LOINC
The current scope of the existing laboratory portion of the LOINC database includes all observations
reported by clinical laboratories, including the specialty areas: chemistry, including therapeutic drug
monitoring and toxicology; hematology; serology; blood bank; microbiology; cytology; surgical
pathology; and fertility. A large number of terms used in veterinary medicine have also been included. In
addition, the scope includes those non-test measurements that are commonly required to interpret test
results and are usually included as part of the report with the laboratory observations. Examples include:
•
•
•
•
for cervical pap smears, the phase of menstrual cycle or use of estrogens
for arterial blood gases, inspired oxygen
for drug concentrations used in pharmacokinetics, the dose
for a blood bank, the number of units dispensed
The June 2000 release contained our first foray into order sets/batteries. Existing LOINC codes could
always be used to order the specific tests observation, but prior to 2000 there was no mechanism to use
LOINC codes to order a set of observations. We have currently only addressed a group of observations
that are either naturally produced as a panel (e.g., urinalysis) or are defined by some national body. For
example, the Basic metabolic 2000 panel that was defined by HCFA (which is now CMS).
The clinical portion of the LOINC database covers tests, measures, and other observations about a patient
that can be made without removing a specimen from them. LOINC has codes for observations like vital
signs, hemodynamics, intake/output, EKG, obstetric ultrasound, cardiac echo, urologic imaging,
gastroendoscopic procedures, pulmonary ventilator management, radiology studies, clinical documents,
selected survey instruments (e.g. Glasgow Coma Score, PHQ-9 depression scale, CMS-required patient
assessment instruments), and other clinical observations.
1.4 The LOINC Code Identifier
To each name, we have assigned a unique permanent code that we call the LOINC code. This is the code
that systems should use to identify test results in electronic reports. The LOINC code has no intrinsic
structure except that the last character in the code is a mod 10-check digit. The algorithm to calculate this
check digit is given in Appendix C. All of the structure associated with a single LOINC entity is stored in
other fields in the LOINC database.
7
2
Major “Parts” of a Test/Observation Name
The fully specified name of a test result or clinical observation has five or six main parts including: the
name of the component or analyte measured (e.g., glucose, propranolol), the property observed (e.g.,
substance concentration, mass, volume), the timing of the measurement (e.g., is it over time or
momentary), the type of sample (e.g., urine, serum), the scale of measurement (e.g., qualitative vs.
quantitative), and where relevant, the method of the measurement (e.g., radioimmunoassay, immune blot).
These can be described formally with the following syntax.
<Analyte/component>:<kind of property of observation or measurement>:<time
aspect>:<system (sample)>:<scale>:<method>
The colon character, “:”, is part of the name and is used to separate the main parts of the name.
The first part of the name can be further divided up into three subparts, separated by carats (^). The first
subpart can contain multiple levels of increasing taxonomic specification, separated by dots (.). The third
and fourth parts of the name (time aspect and system/sample) can also be modified by a second subpart,
separated from the first by a carat. In the case of time aspect, the modifier can indicate that the
observation is one selected on the basis of the named criterion (maximum, minimum, mean, etc.); in the
case of system, the modifier identifies the origin of the specimen if not the patient (e.g., blood donor,
fetus, and blood product unit). The hierarchical structure is outlined in Table 1, with references to the
section numbers where each item is explained in detail.
Table 1: Hierarchical Structure of Fully Specified Analyte Names
Subpart Name
Section
Component/analyte
2.2
Name and modifier
2.2.1
Component/analyte name
2.2.1.1
Component/analyte subname
2.2.1.2
Component/analyte sub-sub-name
2.2.1.3
Information about the challenge (e.g., 1H post 100 gm PO challenge)
2.2.2
Adjustments/corrections
2.2.3
Kind of Property (mass concentration, mass)
2.3
Time Aspect (point or moment in time vs. time interval)
2.4
System/Sample type (urine, serum)
2.5.1
“Super System” (patient, donor, blood product unit)
2.5
Type of Scale (nominal, ordinal, quantitative)
2.6
Method Type
2.7
We used Tietz12, Henry13, IUPAC14, EUCLIDES15, diagnostic microbiology textbooks, such as Mahon
and Manuselis16, the American Association of Blood Banking17, and other sources as well as the expertise
12
13
Ibid.
Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Philadelphia:W.B. Saunders; 1994.
14
15
Euclides Foundation International. EUCLIDES Laboratory Investigation Codes. Available from Dr. Georges DeMoor, Euclides
Foundation International nv, Excelsioriaan 4A, B-1930, Zaventern, Belgium. Phone: 32 2 720 90 60.
16
Mahon CR, Manuselis G (editors). Textbook of Diagnostic Microbiology. Philadelphia:W.B. Saunders; 1995.
17
Walker RH. American Association of Blood Banks Technical Manual. 11th ed. Bethesda, MD: Amer Assoc of Blood Banks, 1993.
8
of the individuals or the committee to choose preferred names.
Examples of fully specified LOINC names:
Sodium:SCnc:Pt:Ser/Plas:Qn
Sodium:SCnc:Pt:Urine:Qn
Sodium:SRat:24H:Urine:Qn
Creatinine renal clearance:VRat:24H:Ur+Ser/Plas:Qn
Glucose^2H post 100 g glucose PO:MCnc:Pt:Ser/Plas:Qn
Gentamicin^trough:MCnc:Pt:Ser/Plas:Qn
ABO group:Type:Pt:Bld^donor:Nom
Body temperature:Temp:8H^max:XXX:Qn
Chief complaint:Find:Pt:^Patient:Nar:Reported
Physical findings:Find:Pt:Abdomen:Nar:Observed
Binocular distance:Len:Pt:Head^fetus:Qn:US.measured
2.1 General naming conventions
2.1.1
Abbreviations in names of component/analyte
Except for enumerated exceptions (Table 2), abbreviations should not be used in the component (analyte)
of the name. We require the use of “total”, not “tot”, “fraction”, not “frac”, “Alpha”, not “A-,” “Beta” not
“B-” (and so on for any Greek letter), “oxygen”, “not O2”, and so on.
Table 2: Example Component Abbreviations
Abbreviation
2.1.2
2.1.2.1
Full Name
Ab
Antibody
Ag
Antigen
DNA
deoxyribonucleic acid
HIV
Human immunodeficiency virus
HLA
human histocompatibility complex derived antigens
HTLV I
Human t-cell lymphotropic virus-I
Ig “X”
immunoglobulins (e.g., IgG for immunoglobulin G, IgM for immunoglobulin M)
NOS
not otherwise specified
RNA
ribonucleic acid
rRNA
ribosomal ribonucleic acid
General naming rules for the component (analyte) part of the fully specified name.
Place the identifier of the substance being measured first. This means “Hepatitis A antibodies
(Ab)”not “Antibodies, Hepatitis A.”
9
2.1.2.2
Use the generic name of a drug, not the brand name, when referring to drug concentrations
and antimicrobial susceptibilities, e.g., Propranolol, not Inderal. We will usually include the
brand or trade names in the related names (synonyms) field.
2.1.2.3
Use full taxonomic name of an organism or virus name (not the disease) when describing a test
that diagnoses that disease. Say “Rickettsia rickettsii Ab” not “Rocky Mountain spotted fever
Ab”. Say “herpes simplex virus Ab” not “HSV Ab.” The disease name should be included as a
synonym in the related name field.
2.1.2.4
Species and groups of species: SP identifies a single species whose identity is not known. SPP
identifies the set of species beneath a genus. We have a third case, however. In some tests,
antibodies apply to different strains of species. In rickettsial diseases, the antibodies are then
against groups of species, e.g., the spotted fever group or the typhus group. In this case we use
Rickettsia spotted fever group and Rickettsia typhus group.
2.1.2.5
When tests include the name of a bacterium (e.g., Neisseria gonorrhoeae DNA probe) for the
formal LOINC name we use the full bacterial name from the International Journal of Systematic
and Evolutionary Microbiology18. When it includes the name of a virus (e.g., West Nile Virus
IgM antibodies), we use the viral name as given by Index Virum19.
2.1.2.6
When the test measures an antigen to a specific species of organism but cross-reactivity is such
that other organisms are identified, the name should be the principal organism that is targeted by
the test.
2.1.2.7
Avoid “direct” and “indirect” except as parts of synonym names. Avoid “conjugated” and
“unconjugated” when a more precise term, such as “glucuronidated” or “albumin-bound” is
available.
2.1.2.8
Use “platelets”, not “thrombocytes.”
2.1.2.9
Name vitamins by the chemical name. For example, use thiamine not Vitamin B1, The name
containing “Vitamin” will be included as a synonym. This is the only reasonable approach
because all vitamins have a chemical name but not all vitamins have a “numbered” vitamin
name. One exception to this rule is that we will use the widely accepted vitamin name for
nutrition intake terms.
2.1.2.10 Always specify whether serology tests measure the antigen or antibody, using the
abbreviation “Ab” for antibody and “Ag” for antigen. Remove the “anti” from “ANTI X Ab.”
It is redundant and obscures the most significant word in the name. Thus, “anti-smooth muscle
Ab” becomes “Smooth muscle Ab.” Common abbreviations or shortened names, e.g., ANA for
anti-nuclear antibody, will be found in the related names field.
2.1.2.11 VDRL will be named Reagin Ab because that is what it is. We will have to depend upon
synonyms and aliases to equate our “standardized” names with the old names.
2.1.2.12 Use the noun form of the target of the antibody, e.g., Myocardium Ab, not Myocardial Ab.
18
Euzéby JP. List of bacterial names with standing in nomenclature: a folder available on the internet. Int J Syst Bacteriol 1997;47:590592. (List of prokaryotic names with standing in nomenclature. [Update 2008 May 2, cited 2008 June]. Available from:
http://www.bacterio.net ).
19
Index Virum, [Internet]. New York: New York, Catalogue of Viruses Version 2, based on the 6th ICTV Report; c2002 [Updated 2007
July; cited 2008 June]. Available from: http://phene.cpmc.columbia.edu/ .
10
2.1.2.13 Anion vs. acid: Always use the anionic name for chemicals, not the acid name, e.g., lactate,
citrate, and urate, not lactic acid, citric acid, and uric acid. The acid form of the name will be
included in the related names field of the database.
2.1.2.14 Alcohols: Always use the single-word names for alcohols: methanol, not methyl alcohol;
ethanol, not ethyl alcohol, and so on.
2.1.2.15 Always spell out OH as Hydroxy, or as - ol, with no space or hyphen between Hydroxy and the
next word.
2.1.2.16 Greek letters, alpha, beta, gamma, etc., are always spelled out (e.g., alpha tocopherol, not A-
tocopherol), with a space between the spelled out Greek letter and the rest of the chemical name
2.1.2.17 Use pH, not log (H+).
2.1.2.18 Whenever possible, the component will contain the scientific names of allergens. NOTE: This is
a convention implemented in January 2002.
2.1.2.19 Avoid use of the word “total” in laboratory test names, except when denoting the denominator of
a fraction. Thus it is Alkaline phosphatase, not Alkaline phosphatase.total, but Alkaline
phosphatase.bone/Alkaline phosphatase.total.
2.1.2.20 For drug metabolites, we will use the “nor” form rather than “desmethyl”, e.g., for instance
nordoxepin not desmethyldoxepin.
2.1.3
Punctuation in analyte names
A number of analyte names include punctuation characters such as commas, for example, to identify the
position of multiple alkyl groups in a carbon chain. We will avoid special characters, e.g., commas,
dashes, and parentheses, except where they are included in the name specified by IUPAC, the Chemical
Abstract Service (CAS) convention, or another international convention. So for example, commas will
appear in multiple substitutions of alkyl chains per the CAS standard, dashes, asterisks and colons will
appear in HLA allele names, colons will appear in the names of some microorganisms, and parentheses
(i.e., round brackets) will appear in the names of red blood cell antigens.
2.1.4
Case insensitivity
All names are case insensitive. Prior to December 2006, we used upper case in the database and our
examples, but change to mixed case for easier readability. In electronic messages senders and receivers
can use upper, lower or mixed case. However, the meanings should not be sensitive to case conversions to
avoid any possibility of confusion when the information is sent over networks that may apply case
conversion. To identify parts of the few names that by international convention are case sensitive, such as
red blood cell antigens, we use the word “little” in front of the letter that is lower case. We use a similar
convention to indicate superscripts with the word SUPER. See examples in Table 3.
Table 3: Example Case Specifying Conventions
Standard mixed case
Our conventions
L little u super little a
Lua
little i-1 subtype
i-1 Subtype
11
2.1.5
Roman numerals vs. Arabic numerals
Whenever possible, numerals shall be represented in their Arabic form. However, when the conventional
name uses Roman numerals, as is the case for clotting factors such as factor VIII, the LOINC primary
name will use Roman numerals and we define a synonym containing Arabic numerals.
2.1.6
Exponents
We will use the phrase “exp” to indicate an exponent in the Component. According to the Unified Code
for Units of Measure (UCUM), exponents are typically represented using an asterisk (*) or carat (^).
However, asterisks and carats both already have defined meanings in the LOINC. (As described later,
asterisks are used in variables that report another specific part of the LOINC name, and carats are used as
delimiters of subparts). For this reason, we use “exp” to avoid ambiguity. For example, the concept
“height raised to the power of 2.7” is represented as “height exp 2.7”.
2.2 Component/analyte (1st part)
The first main part consists of three subparts: (1) the principal name (e.g., the name of the analyte or the
measurement); (2) the challenge or provocation, if relevant, including the time delay, substance of
challenge, amount administered, and route of administration; and (3) any standardization or adjustment.
The three subparts of the first part follow this syntax:
<[analyte].[subclass].[sub-subclass]> ^
<[time delay] post [amount] [substance] [route])> ^
<adjustment>
In the above syntax, the carat (^) is a required delimiter and the “dot” (.) separates the analyte name from
its subspecies.
This convention also implies that dots (.) and carats (^) cannot be a formal part of any of the words that
are connected by these delimiters.
These subparts are described in greater detail below, Sections 2.2.1 through 2.2.3.
2.2.1
Analyte Name (1st subpart)
The first subpart names the analyte, including any relevant sub-classifications, separated from the main
analyte name by dots.
2.2.1.1
Analyte/Subclass
The principal name (the first subpart) can be divided further by subclass (e.g., Calcium by itself is one
component, Calcium.ionized names another test that measures a subclass of calcium.) Subclasses are
separated by dots. Examples of common subclasses include: bound, free, and bioavailable; ionized and
non-ionized; glycated; glucuronidated and non-glucuronidated; IgA, IgD, IgE, IgG, and IgM as modifiers
indicating the subspecies of antibodies. Note that bio-available is distinguished from free by including
both free and partially bound moieties.
12
If the antibody is from a particular subclass of antibodies specify the type of immunoglobulin (IgM, IgG,
IgA, or IgD) e.g., Hepatitis A virus Ab.IgG, Hepatitis A virus Ab.IgM. If more than one subclass of
immunoglobulin is included in the measurement, all are listed in the subclass, e.g., “Mumps virus
Ab.IgG+IgM” with a plus sign (+) to separate the subspecies. There should be no spaces between the plus
sign and the words it connects.
If two or more constituents are measured as one quantity, each constituent should be named and the
component separated by a plus sign, e.g., Cyclosporine+metabolites or Human papilloma virus
16+18+31+33+35+45+51+52+56 DNA.
If multiple analytes are measured separately, the analytes are separated by an ampersand (&) surrounded
by spaces. Two cases that use the ampersand convention are the names of panel terms and impression
terms.
The naming of panel terms is described more completely in Section 8, but here we describe its use of
ampersand. The enumerated child elements of a panel are each measured individually, so we often use
ampersand in the name of the parent term (the panel term), e.g., ABO & Rh group panel. This particular
example of ABO & Rh group also illustrates how panel terms using ampersand are different than an
observation term with ampersand. The ABO & Rh group panel is linked to two separate observation
codes, one for ABO and another for Rh group, that each carries its own result. An ABO & Rh group
observation term would carry a combined (but separately measured) result (e.g. A positive). Either term
could be used in ordering, depending on the reporting approach.
Impressions terms may also use ampersand, for example, Hepatitis A virus Ab.IgM & total impression.
In the case of the Hepatitis antibody impression, both the IgM antibody and the total impression are
described separately.
In some cases, panel or impression Components contain both a plus sign (+) and an ampersand (&), for
example, Human papilloma virus 16 & 18 & 31+33+35+39+45+51+52+56+58+59+66+68 DNA
impression. In this example, the HPV 16 and HPV 18 impressions are both described separately, as is the
impression for the group HPV 31+33+35+39+45+51+52+56+58+59+66+68, which group is measured as
a single quantity.
2.2.2
Challenge test (2nd subpart)
The second subpart contains information necessary to interpret “challenge” (or loading or tolerance) tests.
Variables that report the result of a measurement taken a certain amount of time post challenge (e.g.,
glucose after an oral glucose tolerance test) must be distinguished according to the challenge and the time
post challenge. Thus, the second subpart has a substructure that identifies the time interval or time
difference and the challenge, using the following syntax, where the word “post” (or base line) is required.
<time delay> “post” <challenge>
where the challenge can be further characterized as
<amount given> <substance/treatment given> <route given>
An example of a challenge that used all parts would be: Aldosterone^1H post 25 mg captopril PO
The time difference follows the syntax: n<S|M|H|D|W> where n is a number (possibly a decimal); S
denotes seconds; M denotes minutes; H denotes hours; D denotes days; and W denotes weeks. The time
delay can be preceded by a 'greater than' (>) sign, e.g., >4H. Table 4 lists some possible values for time
difference, but any time specification that follows the above syntax would be legal.
13
In addition to specifying a time elapsed since challenge, the time delay slot can be used to name a clock
time when the measurement was taken, e.g., Glucose^10 AM specimen, or to specify the ordering of
specimens, e.g., ^1st specimen, ^2nd specimen. Use this syntax to indicate pre- and post-immunization
specimens, acute and convalescent specimens, or a series of specimens for which no more detailed
information is available.
Table 4: Example Time Delay Post Challenge
BS
Baseline (time just before the challenge)
PEAK
The time post drug dose at which the highest drug level is reached (differs by drug)
TROUGH
The time post drug dose at which the lowest drug level is reached (varies with drug)
RANDOM
Time from the challenge, or dose not specified (random)
n minutes/hours/days/weeks/months/etc. after challenge begun:
1M
1 minute post challenge
6H
6 hours post challenge
2M
2 minutes post challenge
7H
3M
8H
4M
8H SHIFT
5M
12H
6M
24H
7M
2D
2 days
8M
3D
3 days
9M
4D
4 days
10M
5D
5 days
15M
6D
6 days
20M
7D
7 days
25M
1W
1 week
30M
10D
10 days
1H
8 hours aligned on nursing shifts
1 hour post challenge
2W
2 weeks
1½ hour (90 min) post challenge
3W
3 weeks
2H
4W
4 weeks
2.5H
2½hours post challenge
1MO
1 month (30 days) post challenge
3H
2MO
2 months (60 days) post challenge
4H
3MO
3 months (90 days) post challenge
5H
1.5H
The second subpart is also used to describe measurements taken at a specified point after the beginning of
an ongoing treatment, such as peritoneal dialysis, e.g., Creatinine^12H post peritoneal dialysis. More
generally, this syntax can be used to indicate that observations were recorded, e.g., ^post partum,
^postoperative, or ^post EDTA therapy.
The syntax of the second subpart can be specified in various ways to indicate challenges of greater or
lesser specificity, corresponding to the amount of detail that the laboratory knows about the challenge
specimen.
14
Examples of the range of possibilities include:
Table 5: Example Challenge Subparts
“^”
Time
“Post”
Amount
Sub/Treat
Route
11-Deoxycortisol
^
8H
Metyrapone
PO
^
45M
post
post
30 mg/kg
Corticotropin
dose u/kg
Insulin
Ascorbate
^
post
dose
11-Deoxycortisol
^
2ND specimen
post
XXX challenge
17-Hydroxyprogesterone
^
6H
post
XXX challenge
11-Deoxycortisol
^
post
XXX challenge
Calcium
^
post
CFst
C peptide
^
post
CFst
Analyte
12H
IV
PO
We denote the route of the challenge by HL7 Version 2.3 “abbreviations for medication routes” (Table 6).
An oral route of administration would be denoted by “PO,” 20an intravenous route by “IV.”
Table 6: Example Route Abbreviations for Challenge Part
(from HL7 v.2.3, Chapter 4)
Challenge Description
Abbr.
Abbr.
Challenge Description
AP
Apply Externally
MM
Mucus Membrane
B
Buccal
NS
Nasal
DT
Dental
NG
Nasogastric
EP
Epidural
NP
Nasal Prongs
ET
Endotrachial Tube
NT
Nasotrachial Tube
GTT
Gastronomy Tube
OP
Ophthalmic
GU
GU Irrigant
OT
Otic
IMR
Immerse (Soak) Body Part
OTH
Other/Miscellaneous
IA
Intra-arterial
PF
Perfusion
IB
Intrabursal
PO
Oral
IC
Intracardiac
PR
Rectal
Intracervical (uterus)
RM
Rebreather Mask
Intradermal
SD
Soaked Dressing
Inhalation
SC
Subcutaneous
Intrahepatic Artery
SL
Sublingual
ICN
ID
IH
IHA
IM
Intramuscular
IN
Intranasal
TRH
TP
IO
Intraocular
TRA
IP
Intraperitoneal
Thyrotropin-releasing hormone
Topical
Tracheostomy
TD
Transdermal
IS
Intrasynovial
TL
Translingual
IT
Intrathecal
UR
Urethral
IU
Intrauterine
VG
Vaginal
IV
Intravenous
VM
Ventimask
MTH
Mouth/Throat
WND
Wound
20
In the United States, PO (an abbreviation for per ora) is used to identify medications taken by mouth.
15
Examples:
Glucose^30M post 100 g glucose PO:MCnc:Pt:Ser/Plas:Qn
Gentamicin^trough:MCnc:Pt:Ser/Plas:Qn
For drug peak (obtained at a time presumed to reflect the highest concentration) and trough (obtained at a
time presumed to reflect the lowest concentration) measures, the nature of the substance loaded is the
same as the analyte name, and need not be included.
Reporting the baseline measure as part of a challenge test
2.2.2.1
Through LOINC release 2.52, we have defined one baseline term for different challenge batteries when
the challenge is given by the same dose and route. For example, we define one baseline serum glucose for
the 100 gm oral glucose tolerance test regardless of the number of separate measurements defined in the
battery:
Glucose^pre 100 g glucose PO
A laboratory could use this same test identifier to identify the baseline result of a two hour glucose
tolerance and a three hour glucose tolerance, for example.
However, the number and variety of challenges have been rapidly increasing. Over time it appears
impractical to create a baseline term for every dose and route combination. Furthermore, baseline
measurements are not affected by the subsequent challenge and could in principle be reported simply as
the “unadorned” measurement with no named relation to a coming challenge. Therefore, we are
considering creating only generic baseline “pre challenge” terms, for example, Glucose^pre challenge.
The specifics of the challenge would be reported elsewhere. This proposed approach is an ongoing point
of discussion, and the terms in LOINC release 2.52 follow the original model.
Physiologic challenges
2.2.2.2
Some challenges are defined in terms of a physiologic stress, not a dose of a chemical substance. The
LOINC names currently cover calorie fasts (no calorie intake), exercise, and fluid restrictions. These
challenges are denoted by codes given in Table 7.
In the case of such challenges, the syntax also includes the duration of the challenge. For example:
post <duration><physiologic challenge>
Triglyceride^post 12H CFst
Table 7: Example Nature of Challenge
Type
Description
CFst
Calorie fast. No caloric intake (food) for the period specified in the time part of the term, e.g., POST 12H CFst
Exercise
Exercise undertaken as challenge (can be quantified)
FFst
Fluid “fast.” No fluid intake for the period specified
16
The naming structure is an exact analogous structure to that of chemical challenges. A test for glucose
after 12 hours of an energy fast would be represented as:
Glucose^post 12H CFst:MCnc:Pt:Ser/Plas:Qn
A test for osmolality after a 12-hour fluid restriction would be:
Osmolality^post 12H FFst:Osmol:Pt:Urine:Qn
A test for triglyceride after 12-hour energy fast would be:
Triglyceride^post 12H CFst:MCnc:Pt:Ser/Plas:Qn
Two durations can appear in one specification, for example:
Cortisol^1.5H post 0.05-0.15 U insulin/kg IV post 12H CFst:MCnc:Pt:Ser/Plas:Qn
Our rules for naming challenge tests work well only when there is a single intervention followed by a test
for one or more components over time. Complex challenge tests involving more than one intervention or
complicated sampling techniques need a unique name, but the name may not provide a complete
description of all of the test parameters.
2.2.2.3
Reporting characteristics of challenge as separate observations
Because we cannot anticipate every type of challenge and route of administration, and because some
challenge tests have no usual dose, some challenge tests will not contain a dose. Challenge observations
that do not include a specific dose in the name have the word “dose” where a numeric dose would
otherwise appear. The general form is:
<analyte>^<time> post dose <route>
Examples:
Glucose^1H post dose insulin IV:MCnc:Pt:Ser/Plas:Qn
The actual dose might then be sent as a comment or as a separate “test” that carries the dose as its value.
To accommodate laboratories that wish to transmit the relevant challenge dose as a separate observation,
we also define separate test names (and codes) for reporting such doses. This dose could then be sent by
the reporting service as a separate result in a separate OBX segment.
The name of the observation that identifies the value of the dose would have the form:
<drug or challenge substance>: <time> post dose <challenge substance>
Examples:
Glucose.PO:Mass:Pt:Dose:Qn
Gentamicin:Mass:Pt:Dose:Qn
Thus we distinguish a drug concentration from the drug dose by means of the system (sample), 4th part,
of the test name (see Section 2.5). You can find the observations that carry the dose of drugs or challenges
grouped in the class DRUGDOSE in the LOINC database. This approach has the advantages of
parsimony and practicality. It also provides an observation ID for the piece of information that must be
17
transmitted along with the request for the observation.
Another example would be:
Oxygen:PPres:Pt:BldA:Qn
Oxygen inhaled:VRat:Pt:Inhl gas:Qn (liters/minute or milliliters/second)
Oxygen inhaled mechanism:Type:Pt:Dose:Nom (to report kind of delivery mechanism, e.g., nasal cannula)
An analogous approach is used for reporting many kinds of associated variables when the variables are
not conventionally embedded in the name. We take this approach in part because there are too many
levels of the variables and it is not feasible to represent them all.
2.2.2.4
Generic challenge specifications
We allow for a range of specificity regarding challenges from fully specified to very generic.
Some challenges will be specified fully as described above, e.g., ^30M post 100 g glucose PO. We will
also include: challenges without the amount specified, e.g., ^30M post dose glucose; those that specify a
time elapsed but not a particular challenge, e.g., ^1H post XXX challenge; those that do not specify the
exact time but provide ordering information, e.g., ^2nd specimen post XXX challenge; or even more
generic, ^ post XXX challenge. These latter variants are needed to accommodate challenges that do not fit
any common protocol, or referrals to reference laboratories where the study protocol is not reported.
2.2.2.5
Acute and convalescent, pre and post immunization
To assess the efficacy of immunizations, we measure antibody levels before and after the immunization;
similarly, we obtain evidence for acute infection by assessing acute and convalescent screens. Both of
these cases are reported with the 1st specimen, 2nd specimen syntax, for example:
Acute specimen, 1st specimen, pre-immunization specimen:
Streptococcus pneumoniae Ab.IgG^1st specimen:ACnc:Pt:Ser:Qn
Convalescent specimen, 2nd specimen, post-immunization specimen:
Streptococcus pneumoniae Ab.IgG^2nd specimen:ACnc:Pt:Ser:Qn
2.2.3
Adjustments/corrections (3rd subpart)
The third subpart of the data element contains calculations that adjust or correct some measured value.
We use this subpart to distinguish corrected or adjusted values from the uncorrected measurement, e.g.,
corrected cell counts from the raw cell counts. Since these attributes are unique to each measurement,
they will be short phrases of text rather than a controlled vocabulary to define the content of the third
subpart. However when defined, such a test will have a unique LOINC code and the meaning will be
fixed by the text in the third part.
Examples:
Calcium.ionized^âdjusted to pH 7.4:SCnc:Pt:Ser/Plas:Qn
Leukocytes^^corrected for nucleated erythrocytes:NCnc:Pt:Bld:Qn
18
2.2.4
Distinguishing multiple values for any test via the test name (4th subpart)
HL7 messaging allows for multiple results for one observation. Some systems, however cannot
distinguish separate answers per observation, so they made the test names like organism 1, organism 2 or
substance 1, substance 2 to report multiple organisms or substances identified in samples. We do not
encourage this type of reporting because that distinction can more clearly be accomplished by using one
test name (e.g., organism identified) and the HL7 sub ID to distinguish the multiple
organisms/substances. However, we have created a few terms to accommodate systems that bind the
distinction into their test names. The fourth subpart of the component name will allow reporting of repeat
observations taken at the same time and/or on the same specimen.
Example:
Bacteria identified^^^2:Prid:Pt:Stool:Nom:Culture
2.3 Kind of Property (also called kind of quantity) (2nd part)
The second part of the fully specified name distinguishes between different kinds of quantities relating to
the same substance, e.g., the mass concentration versus the substance (molar) concentration of sodium in
a urine sample, or the absolute eosinophil count versus the percent of the total white count that is made up
of eosinophils. The type of property (kind of quantity) is an IUPAC concept described in the Silver
Book21. We include most of the relevant IUPAC types of property in the LOINC properties table. (See
Table 8 for more examples.)
Main property categories
Mass: Observations reported with mass (milligrams, grams, etc.) in the numerator of their units
of measure have properties that begin with the word mass: mass content, mass concentration, etc.
Substance: Observations reported with moles or mill equivalents in the numerator of their units
of measure have properties that begin with the word substance.
Catalytic activity: Observations that report enzymatic activity have properties that begin with
catalytic, e.g., catalytic concentration, catalytic content.
Arbitrary: Results that report arbitrary units in the numerator of their units of measure have a
property that begins with arbitrary.
Number: Counts are associated with properties that begin with number, e.g., a white blood cell
count reported as number of WBCs divided by volume of blood, would have a property of
Number Concentration.
The pharmaceutical industry has the need for laboratory terms that are not specific as to whether the test
measures a substance (substance concentration or substance rate) or mass (mass concentration or mass
rate). We have created terms with the properties of MSCnc or MSRat to represent these more general test
observations. By default, both RELMA and the online search application (http://search.loinc.org) hide
these terms from the search results, but they can be displayed by adjusting the search limit settings in
these programs.
21
19
Category subtypes: Each of the above major property categories has number of derivatives:
concentration, content, ratio, fraction, and rate (See LOINC properties table).
Concentrations: An amount divided by a volume. These have units such as mg/dL, or gm/L.
Contents: An amount divided by a mass. These have units such as mg/gm sample or mg/total
protein.
Ratios: When a result is reported as one measure divided by another taken from the same system,
the property is a ratio. The ratio of the mass concentration of substance A divided by the mass
concentration of creatinine in a urine sample, for instance, is a mass ratio (MRto). The numerator
and denominator of a ratio must come from the same system. If the measures come from different
specimens, e.g., PT patient/PT control or creatinine serum vs. creatinine urine, it is a relative ratio
(RelRto). The ratio of times coming from an actual and normal control (as in some coagulation
tests) will be relative time (RelTime), a ratio of mass concentrations coming from two different
specimens will be relative mass concentrate (RelMCnc), and a ratio of catalytic concentrations
from different specimens will have the property of relative catalytic concentrate (RelCCnc).
Fractions: Fractions are ratios of a part over a whole: Creatine kinase.MB/Creatine kinase.total,
if measured in grams, is a mass fraction (MFr). Fractions are usually reported as percent. In
Canada and other countries, fractions are measured as pure decimal fraction. For instance, a 95%
O2 saturation would be resulted as 0.95. For some analytes, both styles of reporting are used in
Canada, so we were asked to distinguish decimal fractions from pure fractions. Beginning with
the June 2012 release, we now include terms that have “.DF” appended to the existing fraction
properties. For example, some terms now have properties of “MFr.DF”, “SFr.DF”, “VFr.DF”,
etc. Because of the confusion that occurs in countries that report results as both decimal fraction
and percent, these properties were created to represent decimal fractions that are reported without
units.
Rates: A rate is a measure per a time period, e.g., mg/day would be a mass rate (MRat).
Clearances have the property of volume rate, but “Clearance” will be included in analyte name to
clarify meaning, e.g., Sodium renal clearance:VRat:24H:Urine:Qn
Some measures do not fit the above schema. For instance, IUPAC describes an entitic quantity. This
refers to measure per entity (e.g., cells, receptors, and molecules). Entitic quantities usually have units
that include the name of some entity, e.g., red blood cells (“per 106 RBCs”).
One must be careful when mapping measures of constituents of red blood cells to LOINC code because
they can be expressed many ways, e.g., as an amount “per mass of hemoglobin”, “per liter of blood” or
“per red blood cell”. The first is a mass content, the second a mass concentration, and the last is an entitic
mass (mass per entity) — all different properties.
Some tests report the name of an organism (or initially report the presence of any organism, and later
identify the particular strain), toxic substance, antibody or antigen, as a test result. Use “Prid” (presence or
identity) as the type of property field for results of this sort.
Examples:
Bacteria identified:Prid:Pt:Isolate:Nom:Bacterial subtyping
Barbiturates positive:Prid:Pt:Urine:Nom:Confirm
20
ACnc means the number of arbitrary units in a volume (arbitrary concentration). We originally used
ACnc as a “temporary” place-holder for observations with ordinal answers. We then transitioned to
replacing ACnc with either “Pr” (for results simply based on whether the analyte is present or not without
being determined by a cut off value) or “Threshold” (for observations reported as “positive” or “negative”
based on an internal threshold or cut off). As we updated existing terms with the new model, in many
cases it was difficult to definitively know how results were determined. Therefore, as of release 2.56, we
are using a single property of “PrThr” to represent results based on either the presence or absence of an
analyte regardless of whether or not it is based on an internal cut off. This change was approved by the
Laboratory LOINC Committee in June 2016.The display name will continue to say “Presence”. All of the
existing terms with a Property of “ACnc”, “Pr” or “Threshold” and a Scale of “Ord” were updated to have
the Property “PrThr” for the 2.56 release. A single term with Property “ACnt” and Scale “Ord” was also
updated to have the Property “PrThr.”
Examples:
Clonazepam:PrThr:Pt:Ser/Plas:Ord
Hepatitis B virus surface Ag:PrThr:Pt:Ser/Plas:Ord:Confirm
Burkholderia mallei:PrThr:Pt:XXX:Ord:Organism specific culture
VKORC1 gene.c.1173C>T:PrThr:Pt:Bld/Tiss:Ord:Molgen
The property of “Prid” will continue to be used when the result is selected from a list of organisms, as
described above.
NOTE: For order sets/panels, the property field may be populated by a dash (-).
Correct assignment of properties tends to be the most difficult task for new users of LOINC. Appendix E
provides more explanation and many detailed examples.
Table 8: Example LOINC properties
Enzymatic Activity
CAct
*Catalytic Activity
CCnc
Catalytic Concentration
CRto
Catalytic Ratio
CCnt
*Catalytic Content
CFr
*Catalytic Fraction
CFr.DF
Decimal catalytic fraction
CRat
Catalytic Rate
RelCCnc
Relative Catalytic Concentration
CSub
Catalytic Substance
EntCat
*Entitic Catalytic Activity
EntLen
Entitic Length
EntLogNum
Logarithmic entitic number
EntMass
Entitic Mass
EntNum
*Entitic Number
EntVol
*Entitic Volume
EntSub
Entitic Substance
Entitic
21
EntSRto
Entitic Substance Ratio
Mass
Mass
Mass
ArMass
Mass/Area
MCnc
*Mass Concentration
MCncSq
Mass Concentration Squared
MCnt
Mass Content
MDiff
Mass difference
MFr
*Mass Fraction
MFr.DF
Mass Decimal Fraction
MFrDiff
Mass Fraction Difference
MRat
Mass Rate
MRto
Mass Ratio
RelMCnc
*Relative Mass Concentration
RelMRat
Relative Mass Rate
ThrMCnc
*Threshold Mass Concentration
MCncDiff
Difference in Mass Concentration
Percent Difference in Mass
Concentration
MCPctDiff
Substance (Moles/Milliequivalents)
RelSCnc
*Relative Substance Concentration
Sub
*Substance Amount
SCnc
*Substance Concentration
SCncSq
Substance Concentration Squared
SRto
*Substance Ratio
SCnt
*Substance Content
SFr
*Substance Fraction
SFr.DF
Decimal Substance Fraction
SRat
*Substance Rate
RelSRat
Relative Substance Rate
ThrSCnc
LsCnc
Threshold Substance Concentration
Difference in Substance
Concentration
Log substance concentration
Num
*Number
Naric
Number Aeric (number per area)
NCnc
*Number Concentration (count/vol)
NCnt
Number Content = Count/Mass
NFr
*Number Fraction
NRat
Number=Count/Time
NRto
Number Ratio
LnRto
Log Number Ratio
LnCnc
Log Number Concentration
SCncDiff
Counts
Volumes
Vol
*Volume
22
VCnt
*Volume Content
VFr
*Volume Fraction
VFr.DF
Volume Decimal Fraction
VRat
*Volume Rate
VRatCnt
Volume Rate Content
VRatRto
Volume Rate Ratio
VRto
*Volume Ratio
RelVol
Relative Volume
RelVRat
Relative Volume Rate
ArVol
Volume/Area
ArVRat
Volume Rate/Area
VFrDiff
Difference in Volume Fraction
VPctDiff
Percent Volume Difference
VRtoPctDiff
Percent Volume Ratio Difference
Time
ClockTime
Clock Time
Time
Time Duration
TimeDif
Difference in time duration
TimeFr
Time Fraction
TRto
Time Ratio
TQ2
Timing Quantity 2
RelTime
*Relative Time
Date
Date
DateRange
Date Range
DtTmRange
Date and Time Range
TmStp
Time Stamp—Date and Time
ACnc
Arbitrary Concentration
ACnt
Arbitrary Content
ThrACnc
Threshold Arbitrary Concentration
ARat
Arbitrary Rate
LaCnc
Log Arbitrary Concentration
RelACnc
Relative Arbitrary Concentration
AFr
Arbitrary Fraction
Arbitrary
Other properties
Accel
Acceleration
Addr
Address
Anat
Anatomy
Angle
Angle
Aper
Appearance
Arb
*Arbitrary
Area
Area
ArArea
Area/Area
AreaFr
Area Fraction
23
AreaRto
Area Ratio
Bib
Bibliographic Citation
Circ
Circumference
CircFr
Circumference Fraction
Class
*Class
ColorRto
Color Ratio
Compli
Compliance
CompliRto
Compliance Ratio
Cmplx
Complex
Desc
Description
Diam
Diameter
Dosage
Dosage
Elpot
Electrical Potential (Voltage)
ElpotRat
Voltage Rate (=Amperage)
ElpotRto
Electrical Potential Ratio
EmailAddr
E-mail Address
ArEnrg
Energy/Area
EngCnc
Energy Concentration
EngCnt
Energy Content
EngDiff
Energy Difference
EngFr
Energy Fraction
EngRat
Power = Energy/Time
RelEngRat
Relative Power
EngRatFr
Energy Ratio Fraction
EngRto
Energy Ratio
Enrg
Energy
Equ
Equation
Fcn
Function
Find
Finding
FldConduct
Fluid Conductance
FldResist
Fluid Resistance
Force
Mechanical Force
Freq
Frequency
Hx
History
Imp
Impression/interpretation of study
ID
Identifier
Instrct
Instructions
InvLen
Inverse Length
Inverse VI
Inverse Inspired Volume
Len
Length
LenFr
Length Fraction
LenRto
Length Ratio
LogLenRto
Log Length Ratio
ArLen
Length/Area
Likelihood
Likelihood
24
Loc
Location
LogInvPct
Log Inverse Percent
LogRtoElp
Log Ratio Electrical Potential
MoM
Multiple of the median
Morph
Morphology
NumRange
Number range
OD
Optical density
Osmol
*Osmolality
PctDiff
Percent difference
Pn
Person name
PrThr
Presence or Threshold
Prctl
Percentile
Prid
Presence or Identity
PPres
*Pressure (partial)
PPresDiff
Difference in Partial Pressure
PPresRto
Partial Pressure Ratio
Pres
Pressure
PresRat
Pressure Rate
PressDiff
Difference
PresRto
Pressure Ratio
Quintile
Quintile
Ratio
Ratio
Range
Range
RatDiff
Rate Difference
RelRto
Relative Ratio
Resis
Resistance
ArResis
Resistance/Area
SatFr
*Saturation Fraction
Score
Score
ScoreDiff
Score difference
ScoreRange
Score range
Seq
Nucleotide sequence
Shape
Shape
Susc
Susceptibility
Temp
*Temperature
TempDiff
Temperature difference
Tele
Telephone number
Tscore
T Score
TscoreDiff
T Score difference
Txt
Text
Threshold
*Threshold
ThreshNum
Threshold Number
Titr
Dilution Factor (Titer)
Type
Type
URI
Uniform Resource Identifier
25
Vel
*Velocity
VelRat
Velocity Rate
VelRto
*Velocity Ratio
Visc
Viscosity
Zscore
Z Score
* = from IUPAC Silver Bookxx
2.4 Time Aspect (Point or moment in time vs. time interval) (3rd part)
One can either measure a property at a moment (point) in time or measure it over a time interval and
integrate, in the mathematical sense, over time. In the latter case, we aggregate a “series” of physiologic
states into a single scalar value that reflects some “average” property measured over the specified time
interval. Intervals also have relevance for rate measurements such as excretion (substance rate or mass
rate) or clearances (volume rates). The amount over an interval is often expressed as a mass rate (MRat,
e.g., g/24h) or a substance rate (SRat, e.g., mol/24h). Interval measurements often apply to urine and stool
(e.g., collection over 24 hours and calculation of a concentration, total amount, or clearance). They also
apply to clinical measurements such as urine outputs where we have shift totals and 24-hour totals. Event
counts on physiologic monitors, such as the number of premature ventricular contractions (PVCs) over 24
hours on a Holter monitor, are also of this type, as are look back periods for survey instruments.
The allowed values for non-point time aspect are defined as a syntax exactly like the syntax for the times
in challenge tests, e.g., <numeric value><S|M|H|W> The most common one is 24H. Table 9 gives some
other examples.
For urine collection, 24H is the “standard” integrated measure and these are almost always reported as
mass rates (MRat), substance rates (SRat), or catalytic (CRat) rates. These would contrast with spot or
random urine tests that are represented as point (PT) measures in our nomenclature and usually reported
as concentrations -- MCnc, CCnc, or SCnc for mass, catalytic, and substance concentrations respectively.
However, we can also report the average concentration on a 24-hour specimen – in this case the time
aspect value would be 24H but the property would be MCnc/SCnc/CCnc instead of MRat/SRat/CRat.
The designation of 24H collection is maintained for tests that traditionally have reference ranges based on
amount of substance of a component cleared or excreted in 24 hours. However, a given specimen could
have a 23-hour collection time and would still be called a 24H study. Depending upon the policies and
procedures of the lab, they might extrapolate the reported value to what it would have been if the
collection continued for the full 24 hours and report it as moles per day.
We also allow indirect specifications of a time window. Stdy identifies the duration of the study (without
specifying an exact time); Enctr identifies the Encounter (ER visit, hospital stay, etc.).
Sample volumes reported for timed measurements are carried in other fields or as separate “test” results in
other OBX segments.
26
Table 9: Example Duration Categories
Abbr.
Duration Descriptions
Stdy
To identify measures at a point in time. This is a synonym for “spot” or “random” as applied to urine
measurements.
Duration of the study
Enctr
Duration of an encounter (hospital stay, visit).
Pt
Episode
Episode
Gt 1H
Greater than 1 hour
Ge 1 Hr
Greater than or equal to 1 hour
Lt 1H
Less than 1 hour
Procedure dur
RptPeriod
XXX
* (star)
Abbr.
2.4.1
Duration of the procedure (surgery, etc.)
Reporting period
Not specified; time will be reported in another part of the electronic message
Life of the “unit”. Used for blood products.
Description
Abbr.
Description
Abbr.
Description
1M
1 minute
7H
7 days
5 minutes
8H
7 hours
8 hours
7D
5M
14D
14 days
10M
10 minutes
9H
9 hours
30D
30 days
15M
15 minutes
10H
10 hours
90D
90 days
20M
20 minutes
12H
12hours
180D
180 days
30M
30 minutes
18H
18 hours
1W
1 week
45M
45 minutes
24H
24 hours
2W
2 weeks
90M
90 minutes
48H
48 hours
3W
3 weeks
1H
1 hour
72H
4 weeks
2 hours
1D
72 hours
1 day
4W
2H
1MO
1 month
2.5H
2.5 hours
2D
2 days
2MO
2 months
3H
3 hours
3D
3 days
3MO
3 months
4H
4 hours
4D
4 days
6MO
6 months
1Y
1 year
Lifetime
Lifetime
5H
5 hours
5D
5 days
6H
6 hours
6D
6 days
Time Aspect Modifier
The second and optional subpart of the time component allows an indication of some sub-selection or
integration of the measures taken over the defined period of time: 8H^max heart rate would be the highest
heart rate observed over 8H (Shift). Min, max, first, last, mean are the other possible values for this
subpart. When nothing is stored in this subpart, we assume a mean value over the time period in
questions. Valid values for this subpart are listed in table below.
Table 10: Time Aspect Modifier Codes
Time
Description
min
Minimum value over interval
max
Maximum value over interval
frst
First value observed during an interval
last
mean
Last value observed during an interval
Mean of all of the values observed on the interval (This is the default selection.)
27
2.5 System (Sample) Type (4th part)
System (sample) type is the fourth part of the fully specified test name. It consists of two subparts; the
first part names the system, the optional second part, delimited with a “^”, indicates the super system
source of the sample if it is not the patient, e.g., fetus, blood product unit, donor, etc.
We define different tests for the combination of component (analyte) and type of system (sample) that are
commonly reported. In practice, laboratories include a relatively small range of sample types in their test
names. Chemical tests commonly distinguish between serum, urine, blood, and cerebrospinal fluid.
Microbiology cultures tend to distinguish between greater numbers of sources.
The first part of the system field should be coded using the abbreviations listed in Table 11. Since this list
was defined for reporting sample type in a field of the HL7/ASTM message that is quite independent of
the test/measure name, we do not imply that all such types will find their way into distinct LOINC names.
However, when a distinction by type of system is required in the name, it should be represented by one of
these codes.
For many chemistry tests we have included in the LOINC database a test name for identifying
miscellaneous types of body fluid (Body fld), to provide a way to distinguish tests that are performed on
fluid types that are not explicitly represented in the database. We use “XXX” in the system to identify a
material that is unknown or not specified — it could be solid or fluid, for example. XXX is also used in
the system when the material is specified, but recorded elsewhere in the HL7/ASTM message. Yet, using
XXX as a system can be problematic (see also “Special issues related to XXX as a system” below).
When should we lump a variety of specimen types under the nonspecific “Body fld” and when we should
give a body material its own unique name for a given component? The decision depends upon the degree
to which laboratories have reported the system-component pair as a separate “result” and the degree to
which the normal ranges for a given component-system have been standardized. By this rule, we will
always define different tests for serum and for urine, when a component can be measured in both. We
define sweat sodium as a distinct test because it is a standardized test used to diagnose cystic fibrosis. We
did not define duodenal fluid sodium as a separate LOINC code because this measure has not been
standardized. This does not mean that the specifics about the system would be ignored. It just means that
this information would be recorded in another field of the message (the specimen field of the HL7 OBR
segment), not in the name. Generally, we will specify the type of system to distinguish at least among
blood, urine, cerebrospinal fluid, pleural fluid, synovial fluid, and peritoneal fluid.
For many types of tests, the distinction between plasma and serum is irrelevant. When testing on serum or
plasma is clinically equivalent, the system should be recorded as Ser/Plas, meaning “either Serum or
Plasma”. Sometimes the test can only be run on either plasma or serum; the component will then be
associated with either Ser or Plas in one observation. If the test can be run on either but the results are
different and standardized (a very rare circumstance), two separate tests will be defined in our file, one
with a system Plas and one with a system Ser. The current LOINC database includes some Ser tests and
some Plas tests that should really be Ser/Plas. As we determine that a Ser or Plas test really should have
been designated Ser/Plas, we will change the designation.
As with Ser and Plas, when testing on various specimens is clinically equivalent and the system for the
existing test(s) includes only one or a few of those systems, we will review such tests upon request and
update them as appropriate to include the additional system(s).
28
If the test is run on a combination of specimens (such as a ratio of substance found in CSF and plasma)
the sample types are joined with a “+”, for example, Plas+CSF, Ser+CSF, or Isolate+Ser..
Details about the exact source and collection method (e.g., blood drawn from the right arm and
maintained on ice) are not a proper part of the test name and are reported in other parts of the message.
For example, the SPM specimen segment of an HL7 message can be used to convey detailed information
regarding the type of specimen, where and how it was collected, who collected it, and some basic
characteristics of the specimen. Earlier versions of HL7 used OBR-17 as a field to report specimen
source.
Table 11: Example Laboratory System/Sample Types
Abbr.
Name
Abbr.
Name
Abbr.
Name
Abscess
Abscess
Exhl gas
Exhaled gas (=breath)
Saliva
Saliva
Amnio fld
Amniotic fluid
Fibroblasts
Fibroblasts
Semen
Seminal fluid
Anal
Anus
Fistula
Fistula
Ser
Serum
Asp
Aspirate
Food
Food sample
Skin
Skin
Bil fld
Bile fluid
Gas
Gas
Sputum
Sputum
BldA
Blood arterial
Gast fld
Gastric fluid/contents
Sptt
Sputum - tracheal aspirate
BldL
Blood bag
Genital
Genital
Stool
Stool = Fecal
BldC
Blood capillary
Genital fld
Genital fluid
Sweat
Sweat
BldCo
Blood – cord
Genital loc
Genital lochia
Synv fld
Synovial fluid (Joint fluid)
BldMV
Blood- Mixed Venous
Genital muc
Genital mucus
Tear
Tears
BldP
Blood – peripheral
Hair
Hair
Thrt
Throat
BldV
Blood venous
Inhl gas
Inhaled gas
Platelets
Thrombocyte (platelet)
Bld.dot
Blood filter paper
Isolate
Isolate
Tiss
Tissue, unspecified
Body fld
Body fluid, unsp
WBC
Leukocytes
Tlgi
Tissue large intestine
Bone
Bone
Line
Line
Tsmi
Tissue small intestine
Brain
Brain
Liver
Liver
Trachea
Trachea
Bronchial
Bronchial
Resp.lower
Lower respiratory
Tube
Tube, unspecified
Burn
Burn
Lung tiss
Lung tissue
Ulc
Ulcer
Calculus
Calculus (=Stone)
Bone mar
Marrow (bone)
Urethra
Urethra
Cnl
Cannula
Meconium
Meconium
Urine
Urine
CTp
Catheter tip
Milk
Milk
Urine sed
Urine sediment
CSF
Cerebral spinal fluid
Nail
Nail
Unk sub
Unknown substance
Cvm
Cervical mucus
Nose
Nose (nasal passage)
Vag
Vagina
Cvx
Cervix
Nph
Naspopharynx
Vitr fld
Vitreous Fluid
Col
Colostrum
Penile vessels
Penile vessels
Vomitus
Vomitus
Cnjt
Conjunctiva
Penis
Penis
Bld
Whole blood
Crn
Cornea
Pericard fld
Pericardial fluid
Water
Water
Dentin
Dentin
Periton fld
Peritoneal fluid /ascites
Wound
Dial fld
Dialysis fluid
Dial fld prt
Peritoneal dialysis fluid
XXX
Dose
Dose med or substance
Placent
Placenta
Drain
Drain
Plas
Duod fld
Duodenal fluid
Plr fld
Ear
Ear
PPP
Plasma
Pleural fluid (thoracentesis
fld)
Platelet poor plasma
Endomet
Endometrium
PRP
Platelet rich plasma
Wound
XXX applies when the
specimen can be almost any
kind of specimen or is
unknown. This specimen type
should be used sparingly (see
discussion below). When a test
with this system is used, the
specific specimen for a given
test should be identified in
another part of the message.
29
RBC
Erythrocytes
Pus
Pus
Eye
Eye
RBCCo
Red Blood Cells Cord
These abbreviations are used in the laboratory LOINC codes. Systems in clinical LOINC terms are
spelled out in full and should be easily understood.
2.5.1
Special issues related to XXX as a system
Increasingly we get requests, often from the public health context, for tests with XXX as the specimen.
XXX is a valid LOINC specimen, and often needed in many cases. However, LOINC typically needs a
term with a more specific specimen instead of, or in addition to the XXX. Recall that XXX can be used to
represent any kind of specimen (insects, road kill, and ingested food) when the material is unknown or
specified elsewhere in the HL7/ASTM message. LOINC already has some general specimen terms that
are broad but more constrained than XXX. For example, we have Bld/tiss and Body fld, which represents
fluid from all of the serosal cavities, (though this also deserves discussion). We can create more such
general specimen terms if needed.
Use of XXX for the specimen can create problems. Firstly, the reference ranges for measures on a
continuous scale change with specimen differences, and most systems depend upon the test code to get to
the reference ranges. So using the same code for very different specimens can break the range checking in
many systems. Of course the XXX specimen type is most commonly requested for microbiology tests
used to identify micro-organisms by culture, DNA/RNA or specific antigens. In this case the nature of the
specimen might not change the clinical implication for some organisms; we suspect that anthrax found
anywhere in the body has the same implication. But it does make a big difference for some organisms that
are natural inhabitants of the skin or digestive system, but not of the blood.
Thirdly, if there is no hint of the specimen in the test name, clinicians will have a more difficult time
ordering common microbiology tests. They won’t be able to order urine culture and blood culture each
with a single click, and laboratories will have a more difficult time managing these orders. This is
especially true given the current state of many HL7 messages that only rarely use codes in the specimen
field. (Granted, there is hope for the future). Fourthly, and most importantly, there is the issue of approved
use. Package inserts are very specific and limiting about the specimens for which the test kit is approved.
We have had a recent request for a test with specimen of XXX whose package insert allowed its use only
on Saliva. What do we do? Referral laboratories tend to define tests for class of specimens approved for
use on the instruments/test kits they employ. We have received requests for terms with XXX but the test
is really only used for specimens from body parts that can “catch” STD.
So, the bottom line is that we won’t accept requests for tests with XXX specimens without a narrative
description of the most common specimen and some sense of the range of specimens for which it is used.
We will likely argue for either adding a distinct code for the dominantly common specimen (e.g. Stool for
ameba histolytica) or the specimen prescribed by the package insert, or for entertaining a new specimen
code broader than those now available but narrower than XXX to accommodate a particular need, e.g.
sterile body fluid, or Genital/anal/throat (for STD specimens). This will, of course, take time and
discussion.
30
2.5.2
Super system (2nd subpart)
The second subpart of the system identifies a “super-system” when it is not the patient, e.g., a blood
product unit (BPU), a bone marrow donor, or a fetus. When the super system is not included in a name,
“patient” is the assumed default value. Note: we use the term “fetus” broadly to include embryo, placenta
and products of conception.
For instance, an example of representing a coagulation study that uses measures on both patient and a
control might be:
Coagulation reptilase induced:Time:Pt:PPP:Qn:Coag
Coagulation reptilase induced:Time:Pt:PPP^control:Qn:Coag
Blood banks often report red blood cell antigens for the patient and for each blood product pack assigned
to that patient. So we have:
A Ag:PrThr:Pt:RBC:Ord
A Ag:PrThr:Pt:RBC^BPU:Ord
Note: The inclusion of the super system as part of the system represents a change from versions of
LOINC prior to Release 1.0K, May 1998. Earlier versions included this information in the (no longer
valued) fourth subpart of the component.
2.6 Type of Scale (5th part)
The fifth data part of the test name specifies the scale of the measure, and is a required part. The
abbreviation of the type of scale (previously called precision), given in Table 12, should be used in the
fully specified name. Note that with the release of Version 1.0K, May 1998, we changed the codes for
these from SQ to ORD and from QL to NOM to more accurately identify the meaning.
Table 12: Type of Scale
Scale Type
Abbr.
Description
Quantitative
Qn
Ordinal
Ord
Quantitative or Ordinal
OrdQn
Nominal
Nom
Narrative
Nar
“Multi”
Multi
Document
Doc
The result of the test is a numeric value that relates to a continuous numeric scale.
Reported either as an integer, a ratio, a real number, or a range. The test result value may
optionally contain a relational operator from the set {<=, <, >, >=}. Valid values for a
quantitative test are of the form “7”, “-7”, “7.4”, “-7.4”, “7.8912”, “0.125”, “<10”,
“<10.15”, “>12000”, 1-10, 1:256
Ordered categorical responses, e.g., 1+, 2+, 3+; positive, negative; reactive,
indeterminate, nonreactive. (Previously named SQ)
Test can be reported as either Ord or Qn, e.g., an antimicrobial susceptibility that can be
reported as resistant, intermediate, susceptible or as the mm diameter of the inhibition
zone. (Previously named SQN) We discourage the use of OrdQn in other circumstances.
Nominal or categorical responses that do not have a natural ordering. (e.g., names of
bacteria, reported as answers, categories of appearance that do not have a natural
ordering, such as, yellow, clear, bloody. (Previously named QL)
Text narrative, such as the description of a microscopic part of a surgical papule test.
Many separate results structured as one text “glob”, and reported as one observation, with
or without imbedded display formatting.
A document that could be in many formats (XML, narrative, etc.)
Set
Set
Used for clinical attachments
31
Quantitative (Qn) identifies scales that can be tied to some physical quantity through a linear equation.
This means that if we have two reports for the same quantity one with a value of 5 and the other a value
of 10 we know that the two are related in amount through the linear equation Y = aX +b. When the
intercept, b, is non-zero, we have a difference scale. (Fahrenheit temperature is a difference scale.) When
it is zero we have a ratio scale (Kelvin temperature is a ratio scale).22,23A Qn value may be reported as a
value for a “continuous” scale, as is the case for serum sodium, or it may be reported from a series of
discrete values, as is the case for titers, e.g., 1:16, 1:32.
Ordinal (Ord): Some observations have values that are well ordered, e.g., “present, absent”, “1+, 2+, 3+”,
or “negative, intermediate, positive”, but the values have no linear relationship to one another. We do not
know that positive is two or three times as much as intermediate, we just know that positive is more than
intermediate. These kinds of observations have an ordinal scale (Ord). Tests with “yes/no” answers are
always ordinal (Ord). Tests reported as negative when less than the detection level but as quantified
values otherwise should be regarded as quantitative (Qn).
Quantitative/Ordinal (OrdQn): Rarely, a result can be reported in either an ordinal or quantitative scale.
The principal example of this scale is a MIC, which can be reported as either
resistant/intermediate/susceptible or by the MIC numeric value. The need for terms with OrdQn as scale
was further obviated by clarification from HL7 that results such as "POS" and "NEG" should go in the
OBX-8 field for normalcy status. Thus, LOINC codes with scale of Qn can be appropriately used in these
cases even if the "values" coming back are coded interpretations of the true numeric result value.
Nominal (Nom): Some observations take on values that have no relative order. Think of the numbers on
football jerseys. These simply identify the players; they do not provide quantitative information or rank
ordering of the players. We refer to these as nominal (Nom) in scale. Blood culture results provide a good
example. Possible values could be Escherichia coli (or a code for E. coli) or Staphylococcus aureus. Other
examples are admission diagnoses and discharge diagnoses. Any test or measure that looks broadly at
patient or specimen and reports the name of what it finds is a Nom scale. The values of nominal scaled
observations are assumed to be taken from a predefined list of codes or from a restricted vocabulary (e.g.
a menu of choices). These observations would typically be sent in an HL7 message OBX segment with a
Coded Element (CE) data type (in earlier HL7 versions) or its superseding Coded with No Exceptions
(CNE) and Coded With Exceptions (CWE) variants (later HL7 versions). It is important to note that the
CE and CWE data types allow values to be set as codes with their print text or just as their print text
alone. These data types and the Nom scale would not be used for running narrative.
Narrative (Nar): Some observations are reported as free text narrative. The content is not drawn from a
formal vocabulary or code system. A dictated present illness would be an example of a scale of narrative
(Nar). Many clinical LOINC codes will come in two versions: one for the nominal (coded) version and
one for a narrative (free text) version.
We strongly encourage all reporting to be at the most granular level of detail. That is, if three numbers
were reported, they would each be reported under a unique LOINC code and transmitted in a separate
HL7 OBX segment. Occasionally reporting systems are not able to comply with this dictum. For example
some chromatography instruments can identify chemicals from the entire spectrum of known chemicals
(CAS identifies more than 10 million distinct chemicals) and we may not have specific LOINC codes for
reporting out these details. We have designated the scale of Multi to identify results that include many
22
Stevens SS. Measurement, statistics, and the chemapiric view. Like the faces of Janus, science looks two ways – toward schematics
and empirics. Science 1968;161:849-856.
23
Tang YW, Procop GW, Persing DH. Molecular diagnostics of infectious diseases. Clin Chem 1997;11:2021-2038.
32
separately structured results as one text “glob” with or without imbedded (display formatting). Some
laboratories report all of the details of many multiple measure tests under such globs with test names that
correspond to their order name. We strongly discourage such reporting. It defeats the very purpose of
individual codes to tag content.
Note: Because the individual components of an Order set/Panel often have different scales, the scale for
the order set term may be populated by a dash (-).
2.7 Type of Method (6th part)
The method by which the test was performed is the sixth part of the test name. Methods need only be
expressed as part of the name when they provide a distinction between tests that measure the same
component (analyte) but which have different clinical significance or have a different clinical reference
ranges. For instance, whole blood glucose tested with a test strip might be distinguished in the method
field.
The list of methods given in Table 13 is not exhaustive; we have included only those methods that are
abbreviated in the database or which otherwise require explanation or clarification. Most methods are
fully spelled out in the database and should be self-explanatory.
Laboratories do not include the method as part of the name for most common chemical and hematological
tests. They often need the freedom to choose the instrument according to time of day, urgency of the
request for service, availability of the instruments and so on, even though the instruments may employ
different methods. The laboratories then adjust each of the “interchangeable” instruments to produce
equivalent results even though the instruments may use different methods. Therefore, we do not want to
distinguish too finely on the basis of methods. When a LOINC term does include a method, it usually
describes a type or class of method and does not make fine-grained distinctions except in special cases.
Though method is rarely significant for many chemical and hematological tests, it is often important to
immunochemical/serology testing, because the sensitivity and specificity of some tests varies greatly with
the method. For this reason, you will commonly see methods included in microbiology tests and
coagulation tests within the LOINC database.
This does not mean that detailed information about the method is irrelevant, but that it is not always
useful or practical to bind it to the test name. It is an essential element of the internal quality assurance of
laboratories and there are fields for reporting other details about the method in HL7 and CEN TC251 test
result messages.
Table 13: Laboratory Method Type Abbreviations
Method
Abbr.
Agglutination
Aggl
Coagulation Assay
Coag
Complement-dependent
Cytotoxicity
Complement Fixation
Comp fix
Cytology Stain
Cyto stain
DNA Nucleic Acid Probe
Chromogenic/Enzymatic Assay
Comment
To distinguish coagulation assays based on clotting methods that test
function/activity from Immune methods that detect the presence of clotting
factors and may or may not be functional assays.
CDC
Probe
Chromo
The staining method used for pap smears, fine needle aspirates and other
cell stains.
See section 2.7.1 for more information about probes.
To distinguish coagulation assays based on chromogenic (enzymatic)
33
activity.
Immunoassay
IA
Flocculation Assay
Floc
Hemagglutination Inhibition
HAI
Hemagglutination
HA
Immune Blot
IB
Immune Fluorescence
IF
Latex Agglutination
LA
Encompasses all immunoassays with a few exceptions, including Immune
Blot and Immune Fluorescence, which were created based on historic
usage.
Encompasses direct and indirect
Encompasses DFA, IFA, FA. Usually applies to cells and smears
examined microscopically so that both the “where” and the “what” can be
assessed, but can also be used on fluids in a way similar to ELISA.
Leukocyte Histamine Release
LHR
Minimum Inhibitory Concentration
MIC
Antibiotic susceptibilities
Minimum Lethal Concentration
MLC
Also called MBC (minimum bactericidal concentration)
General class of methods used to detect genetic attributes on a molecular
basis including RFL, PCR and other methods.
Molecular Genetics
Molgen
Neutralization
Neut
Radioimmunoassay
RIA
Rapid Plasma Reagin
RPR
Serum Bacterial Titer
SBT
Rapid Plasma Reagin
RPR
Vertical Auto Profile
VAP
Visual Count
Venereal Disease Research
Laboratory
VC
2.7.1
VDRL
Microscopic flocculation test, using cardiolipin-lecithin-cholesterol
antigen with carbon particles.
Determines the serum dilution that is capable of killing microorganisms.
Microscopic flocculation test, using cardiolipin-lecithin-cholesterol
antigen with carbon particles.
Developed by Atherotech, Inc.
Microscopic flocculation test
DNA/RNA probes/measures
We distinguish three kinds of DNA probe methods:
1. Probe without amplification (Probe)
2. Probe with target amplification (Probe.amp.tar)
a. See Table 14a for a list of methods that would be identified as Probe.amp.tar in the
method part of the LOINC term.
3. Probe with signal amplification (Probe.amp.sig)
a. See Table 14b for a list of methods that would be identified as Probe.amp.sig in the
method part of the LOINC term.
Table 14a: Examples of specific methods that would be classed as target amplified DNA/RNA
Probe.amp.tar (includes nucleic acid target amplification and probe)
PCR*
Polymerase Chain Reaction
TMA*
Transcription Mediated Amplification
NASBA*
Nucleic Acid Sequence Based Analysis
Applies to DNA, RNA
Roche Molecular Systems (thermal cycler)
Requires repeated cycles of heating and cooling-each cycle doubles the target
Applies to DNA, RNA
Gen-Probe, Inc. (isothermal)
Applies to RNA, DNA
Organon-Tenika Corp (isothermal)
34
SDA*
Strand Displacement Amplification
LAT*
Ligation-Activated Transcription
3SR SR*
3 Self-Sustaining Sequence Replication
LCR*
Ligase Chain Reaction
QBR*
Q-Beta Replicase or probe amplification
category method
Applies to DNA
Becton Dickinson (isothermal)
Applies to RNA, DNA
Bartel's Diagnostic (isothermal)
Also probe amplification category method
Abbott Laboratories (thermal cycler)
Applies to DNA RNA
Gene Track Systems. (isothermal)
Table 14b: Examples of specific methods that would be defined in LOINC as signal amplification methods
Probe.amp.sig (includes nucleic acid signal amplification and probe)
HPA*
Hybridization Protection Assay
bDNA*
Branched Chain DNA
---------
Applies to RNA
Gen-Probe Accuprobe
Applies to DNA, RNA
Chiron Corp (isothermal)
Hybrid Capture
*The items in the first column of the above table are not meant to be used as methods in LOINC terms.
2.7.2
PCR assays with non-probe analyte detection methods
In LOINC version 2.54, we added a new method for target amplification with melt curve analysis
(Melt.amp.tar) to distinguish assays that use melt curves rather than probes for analyte detection. For
version 2.56, we created a more encompassing non-probe based method (Non-probe.amp.tar) that is used
for any PCR assay with non-probe based detection technology, including melt curve analysis, and which
still distinguishes from probe-based assays (Probe.amp.tar). The existing terms with the Melt.amp.tar
method were updated to use the Non-probe.amp.tar method for the 2.56 release.
2.7.3
Immune Assays
Immune assays in the LOINC world include a large swath of tests. We have historically lumped together
immune assays that detect the linking of antigens and antibodies via special signaling mechanisms, such
as EIA, ELISA, chemiluminescence and other similar tests that produce one measure (quantitative or
qualitative) of the analyte of interest. We thought of this class of tests as “EIA-like” and in the absence of
an existing short acronym to describe their constituents, we borrowed “EIA” to provide this meaning in
the Short Name and used Immunoassay in the Long Common Name to signal that this method type was
not limited to pure EIA tests. In LOINC version 2.56, we changed the name of the EIA method to IA (and
EIA.rapid to IA.rapid), in order to mitigate some of the confusion regarding the EIA name. The Long
Common Name will continue to use Immunoassay as it always has, and the Short Name will use IA rather
than EIA.
Some immunologic tests have always had their own method type and were never lumped in the category
of EIA-Immune assays described above. Immune blot (IB) tests, immune diffusion and immune based
flow cytometry (FC) tests have always had specific method names. They are different because they
usually yield multiple related observations. Immune fluorescence tests (IFA, DFA and ACIF) also have
had their own method type, namely IF, because they can provide information about the presence or
amount of a target analyte and its location on a smear, tissue slice or cell (though all IF tests do not
provide such location information). LOINC has also assigned distinct method types to some other
immunologic tests including VDRL, Latex fixation and other kinds of agglutination tests because these
were their historic names or they had specialized uses or limits.
We classify peroxidase and all other non-IF immune stains of tissue under the method category immune
35
stain.
2.7.4
Coagulation
We distinguish among three kinds of coagulation methods: coagulation (Coag), which measures the
coagulation activity, immune (Imm), which measures the amount of the coagulant protein, not its activity,
and chromogenic (Chromo), which measures the coagulation factor via enzyme rate (also called
enzymatic).
2.7.5
Stains
We provide very detailed distinctions among various tissue stains, naming them in full. Stain methods
that are modifications of a basic method are named using a <basic>.<modification> syntax, e.g.,
Methenamine silver stain.Jones
2.7.6
Substrates used to measure enzyme activity
For tests that are measuring enzyme activity using various substrates, the name of the enzyme or enzyme
group will be the Component and the substrate will be the Method:
Mitochondrial respiratory chain enzymes: CCnt: Pt: Fibroblasts: Qn: 1-14C-glutamate substrate
2.7.7
Clinical measures
We distinguish reported from estimated and measured value. For example, reported body weight is the
stated weight from a patient or surrogate. Estimated body weight is estimated by an observer, and
measured would be the body weight as measured on a scale.
2.7.7.1
Oximetry
Use of “oximetry” as a Method can cause confusion. For details see the Oxygen Saturation Technical
Brief at the end of this guide, but briefly, oximetry has several specific types, including pulse oximetry,
co-oximetry and heme-oximetry. Unfortunately, at one time the word “oximetry” was used
interchangeably with “pulse oximetry,” which created confusion in LOINC because we have one method
called oximetry and another called pulse oximetry. To avoid ambiguity, as of version 2.54 we deprecated
most of the terms with oximetry as the Method, and moving forward we will continue to review the ones
that are remaining and create new terms with the Method pulse oximetry as needed.
2.7.8
Imaging studies
We distinguish among the major imaging modalities for most measures derived from such imaging
studies (e.g., cardiac outputs from a MUGA scan, angiography, 2D Echo, Doppler, etc.).
2.7.8.1
Methods that include imaging modality and calculation
In some cases, the Method includes two concepts: the imaging modality and the method of calculation for
the specific measure. Through LOINC version 2.50 we used the pattern <imaging
36
modality>.<calculation>, for example, US.2D.Teichholz. This format, however, does not clearly
differentiate between the two distinct concepts being represented. This is further complicated by our
convention of using a dot (.) to specify the submodality (e.g. 2D). Beginning in LOINC version 2.52, we
plan to separate the two concepts with a plus (+) rather than a dot (.), so that US.2D.Teichholz becomes
US.2D+Calculated by Teichholz method. We will apply this format to new terms moving forward and
plan to update existing terms over time.
2.8 Use of curly braces {} in LOINC names
In Section 2.5 we described the use of XXX in the System when the material is unknown or specified
elsewhere in the HL7/ASTM message. In some domains, particularly clinical observations, we have
adopted a newer style of notation with curly braces to indicate that the information is provided elsewhere.
For example, LOINC term 32491-3 represents a deep tendon reflex observation where the anatomic
location is not specified in the term name:
Deep tendon reflex:Find:Pt:{Reflex location}:Ord:Observed
Such terms could be used in post-coordinated expressions where the value of “reflex location” is
communicated elsewhere. The curly braces notation has the advantage over using XXX in some cases
because it allows a more precise indication of the set of possible entities to expect for that piece of
information. In the reflex example above, saying {reflex location} narrows the expected set of possible
values down to those anatomic regions where a muscle tendon reflex can be observed.
We have made use of this notation primarily in the System and Method part of the name.
2.9 Short Convenient Names
As of the August 2002 release of LOINC we have included a new field in the LOINC database called
“SHORTNAME”. This field will carry a short, mixed case name for the LOINC concept. We have
populated these fields for all laboratory and radiology tests. Our goal was to produce names no longer
than 30 characters in order to fit within the space allocated by most laboratory reporting systems. In
contrast to the formal LOINC name, case is significant in the LOINC short name. When possible, we
have used common acronyms and common names rather than the more formal name rules of the full
LOINC name. For example, we used the English names of allergens in the short names rather than the
formal Latin species names (in part because they were shorter). The LOINC short names are subject to
change and should not be used as identifying keys in any database.
These names have been created via a table driven algorithmic process. We have used all upper case to
represent acronyms, and mixed case in organism names as specified in naming conventions (e.g., genus is
capitalized, species is not). For virus names we used the acronym assigned by Index Virum where
available.
2.10 Long Common Names
LOINC has received periodic requests from users to produce “pretty” display names that could be used in
user interfaces, etc. While systematically created names (like the standard LOINC short names) can be
37
guaranteed to be unique, they are sometimes not the most user-friendly. We have always expected that
users would link their own local preferred names to LOINC terms for use in reports and displays. In
contrast to systematically-created names, user-friendly names are often ambiguous.
After collecting and reviewing display names from several sources, we decided to create a new
algorithmically-generated Long Common Name based on patterns we observed. As of the January 2009
release, we have included a new field in the LOINC Table called “LONG_COMMON_NAME”. These
names have been created by an algorithmic process and are checked for uniqueness. Most abbreviations
and acronyms that are used in the LOINC database have been fully spelled out in English. For allergens,
the common English names are used instead of the more formal Latin species names. For coagulation, the
more commonly used phrases such as “Prothrombin time” have been used.
We started creating long common names first for laboratory terms, but are now producing them for all
terms. The text strings for the long common names are subject to change over time as we continue to
refine the algorithmic process and collect feedback from users. In particular, many of the long common
names for clinical terms have not had as intense focus as the laboratory terms have, so we expect these to
be refined over time. In LOINC release 2.54, many of the echocardiography and ophthalmology were
updated based on input from DICOM and the National Eye Institute, respectively.
2.11 Classes
We assign each LOINC term to a general category called a Class. These categories are relatively broad
and are intended to make it easier to sort and browse the database. They are not intended to be binding
definitional characteristics of the term, and we may refine them over time. A more detailed listing of the
Classes is presented in Appendix B. Throughout this document many of the naming conventions and
approaches are described in reference to a Class of terms. Here we provide a bit of explanation about
some of the laboratory term classes.
The class of Microbiology includes all tests used to identify microorganisms and evidence for infection
by specific organisms as well as cultures direct microscopic exams that identify organisms or prove
evidence for present or past infection with specific organisms. Microbiology includes tests for antibodies,
antigens, DNA and RNA. The Serology class does not include measures antibodies or antigens related to
microorganisms. Molecular pathology class does not include RNA or DNA based tests for infectious
organisms. (They are all included in Microbiology.)
The class Blood bank includes all blood bank testing including ABO-Rh testing. Allergy class includes
testing for antibodies to allergens (cat dander, trees, etc.). Serology includes rheumatological, and
autoantibodies, and antigen measures not covered by these two classes. Hematology/cell counts exclude
coagulation studies that are found in a separate class. Measures of complement activity are included
within Hematology, not Chemistry. Chemistry does not include challenge tests such as Glucose tolerance,
ACTH stimulation, etc.; these are in a separate category called Challenge tests.
3
Special Cases
3.1 Findings viewed as variables or as values
For some complex tests there are two ways to organize the results into a report.
38
3.1.1
Value
Assume a set “X” is made up of five “results” that can have a scale of (absent present) or (0 1). These
results could be reported as:
Finding 1 =
Finding 2 =
Finding 3 =
Finding 4 =
Finding 5 =
Present
Absent
Present
Absent
Absent
- or - or - or - or - or -
1
0
1
0
0
Each finding is then considered a binary variable. This is sometimes called a “panel” approach.
3.1.2
Variable (Multiple Choice) Approach
The alternative would be to report this information as a single variable (or multiple-choice question) with
many possible values:
Variable X - Finding 1, Finding 3
In this case the findings are the values of a variable called Variable X; only the positive findings are
reported as values. Many laboratory tests, e.g., those that test for HLA antigens, red blood cell antigens,
or screens for toxic substances, could in theory be presented either way. The microscopic part of the
differential count and urinalysis could also be described either way. History and physical findings and
(given a real stretch) even culture results could be structured in the panel or multiple choice/multiple
answer format.
A single lab may report red blood cell antigens in either way, as a binary panel or a multiple-choice result,
depending upon the purpose of the test. The routine cross and type are reported out in the multiple choice
pattern format (only positives from a modest fixed set of tested antigens are reported). But if the tests are
being used to prove fatherhood, the results are usually reported as a binary panel.
Blood cultures could in theory be regarded as panels:
Test Name
Escherichia coli
Staphylococcus aureus
Diphtheroids
Streptococcus pneumoniae
Pseudomonas aeruginosa
Value
absent
present
absent
absent
present
Although in practice such tests are almost always reported in the multiple choice/multiple answer format,
as follows:
Test Name
Blood culture
Values
P. aeruginosa, S. aureus
We bring up these issues to explain why we use a somewhat different data format for some types of tests,
and why we sometimes provide for both reporting methods (e.g., HLA blood cell antigen tests) in the
LOINC database. When a binary scale is used, the scale will be ordinal (Ord) and the kind of property
will usually be presence (PrThr, for results based on the presence/absence of an analyte regardless of
whether an internal cut off value is used to determine the ordinal result). When the multiple-choice
39
multiple-answer approach is used, the scale will be nominal (Nom) and the type of property will be
presence or identification (Prid).
3.2 Blood bank
Red cell antigens will be named in accordance with the American Association of Blood Banking (AABB)
naming standards.24 In addition to the antigen or antibody, a modifier would be included in the supersystem (the second subfield of the System field); to indicate whether testing was performed on the patient,
donor, or blood product. Unless explicitly stated, testing is assumed to have been on a material collected
from a patient. Additional information about the person identified in the fourth subpart, such as the
donor's name or relationship to patient, should be placed in other OBX segments, or comment segments
of the message, and would not be part of the test name.
Blood bank reporting illustrates the need for a method of reporting by panel and by multiple-answer
mechanism. The LOINC database provides observation names for both kinds of reporting.
3.2.1
Panel reporting:
Each reportable antigen must have its own test, so that each element in a full set of binary tests could be
reported as (negative, positive) or (0, 1).
The fully specified names of A, AB, B, and O blood types (as observations) would be as follows:
Measure of serum antibody against type A blood of donor:
A Ab:PrThr:Pt:Ser/Plas^donor:Ord
Presence of A antigen on donor's red blood cells:
A Ag:PrThr:Pt:RBC^donor:Ord
Presence of A antigen on the blood cells in a pack of blood given to the patient:
A Ag:PrThr:Pt:RBC^BPU:Ord
3.2.2
Multiple answer reporting:
All blood antibodies found (or not found) can also be reported in one result term:
Antigens absent:Prid:Pt:BBL^BPU:Nom
Antibodies identified:Prid:Pt:Ser/Plas:Nom
The LOINC database provides other “observations” for reporting: the status of each blood pack (e.g.,
held, given, discarded), and for reporting that information when HIS and medical records systems want it;
how much of each type of blood product was given at a moment in time; the type of each pack; any
adverse reaction to that pack; and the pack number to accommodate laboratories that send this
information as discrete observations.
Blood product disposition:Type:Pt:^BPU:Nom
24
Walker RH. American Association of Blood Banks Technical Manual. 11th ed. Bethesda, MD: American Association of Blood Banks,
1993.
40
Blood product type:Type:Pt:^BPU:Nom
3.3 Immunocompetence studies (flow cytometry)
The CD (Cluster of Differentiation) markers in the LOINC database include all of the single markers and
the most commonly reported combinations, e.g., CD11C+CD20C+. Most of these are really measuring
the number or percent of cells that bear the specific T-cell marker pattern, in which case they should be
specified as a subtype of a lymphocyte, e.g., Cells.CDx. There are other possibilities, and these cell types
can also be named; for instance Blasts.CD2 or Abnormal blood cells.CD5. LOINC Components for cells
with single markers typically do not include a plus or minus sign after the marker because flow cytometry
labs do not report single CD marker-negative results, so when the marker is reported, the plus is implied.
In other words, the LOINC Component Cells.CD4 represents the presence of CD4, and we do not have a
Cells.CD4- Component, because such a result is not reported. However, when multiple markers per cell
are reported, the plusses and minuses are always included, for example, Cells.CD3-CD8-CD57+.
Two kinds of measures are of interest.
3.3.1
Number of cells containing the marker
The “absolute” number of such cells per cubic millimeter is represented as number concentrations, for
example:
Cells.CD16C+CD56+:NCnc:Pt:Bld:Qn
3.3.2
Percent of cells containing the marker
Percent of cells containing the named marker per 100 cells of that type is represented as number fraction,
for example:
Cells.CD16C+CD56+/100 cells:NFr:Pt:Bld:Qn
3.4 General approach to microbiology results
The inherently complex structure of the results of microbiological cultures presents unique challenges for
the goal of standardized observation names.
Result Status (Preliminary, Final) should not be reported as a separate observation or as part of the name.
It should be reported in the Result Status field (OBR-25) of the HL7 OBR segment.
Specimen Type (Serum, Blood, Urine, etc.) will be indicated in the HL7 OBR segment with the
Specimen Source field (OBR-15), but may also be represented in the name.
Details of specimen collection will usually be noted as OBX segments or comment segments that
accompany the culture result message. The observation identifier for the OBX segment will have the fully
specified name of “Specimen collection description:Find:Pt:*:Nom” and the Observation Sub-ID field
will be used to order or group sets of observations. That is, if the material was collected by swabbing a
wound of the right upper arm, multiple OBX segments would be created, each with the name “Specimen
collection description:Find:Pt:*:Nom” and the Observation Results fields of the OBX segments would
contain respectively “Swab,” “Right,” “Arm,” and “Wound.” (The granularity of the actual terms used in
the specimen description is at the discretion of the user. Thus, “Right Arm Wound” as the value of a
single OBX segment could be used in place of the three codes described in the previous sentence.)
41
Descriptions of measurement and culture growth will be noted as separate OBX segments that
accompany the culture result message. The name of the observation identifier will provide the context of
the observation. For instance, the name for a quantitative test of bacteria in a specimen would be:
Colony count:Num:Pt:XXX:Qn:VC
Descriptions of Gram stain findings will be noted as OBX segments that accompany the culture result
message. The name of the observation identifier will be:
Microscopic observation:Prid:Pt:XXX:Nom:Gram stain
The result values that could be reported with this test (which is a multiple-choice, multiple answer type or
observation) might include one or more of the following:
Epithelial cells
Gram-positive cocci in chains
Many Gram-negative diplococci
The organisms identified in a culture will be sent as result values in OBX segments. LOINC provides
codes to identify the observation, but not for identifying the names of organisms that would appear as
result values (i.e. in OBX-5). SNOMED CT is an appropriate source for these organism concepts.
While “Throat Culture” is the source of the culture inoculum, it is also a label that indicates what kind of
media was inoculated and the other techniques used in the laboratory. So, it is a short hand for a kind of
method and such will be recorded as the method part of the name. Thus, “Throat Culture”, “Blood
Culture”, and “Clostridium difficile Culture” all represent labels for how a culture was performed.
The LOINC naming model for routine cultures is:
Bacteria identified:Prid:Pt:<specimen>:Nom:Culture
Examples names include:
Bacteria identified:Prid:Pt:Bld:Nom:Culture
Bacteria identified:Prid:Pt:Brn:Nom:Culture
Bacteria identified:Prid:Pt:Stool:Nom:Culture
The LOINC names for cultures are based on the expected observations they generate, e.g. “bacteria
identified” or “virus identified”. For most routine cultures the users are looking for bacteria. However, in
some cases a routine culture may also grow out some fungi like yeasts. Such observations can also be
reported under the same test code. But, since the culture would not be optimized for growing out fungi we
have a bacteria-focused name.
It is worth emphasizing these culture terms are intended for use as both as orders and observations despite
having a more result-oriented name. Furthermore, as a matter of good clinical practice, most laboratories
perform susceptibility testing on any significant isolate on a reflex basis. So there is no need for codes
that say “culture and sensitivity” because it is implied. Thus, an order for 17928-3 “Bacteria identified in
Blood by Aerobe culture” would likely trigger several workflow steps, including bottle blood culture,
bacteria isolation, identification, and antimicrobial susceptibility testing (which would be reported with
appropriate susceptibility terms as described in Section 3.5).
42
LOINC names for methods of staining a sample/material directly (where many descriptive observations
are possible) include:
Microscopic observation:Prid:Pt:XXX:Nom:Gram stain
Microscopic observation:Prid:Pt:XXX:Nom:Dry mount
Microscopic observation:Prid:Pt:XXX:Nom:India ink preparation
Microscopic observation:Prid:Pt:XXX:Nom:Trichrome stain
Microscopic observation:Prid:Pt:XXX:Nom:Giemsa stain
Names for results of staining procedures performed on organisms that are growing in culture will use
Isolate as the system/sample type. For example:
Fungus identified:Prid:Pt:Isolate:Nom:Fungal subtyping
Names for organism-specific cultures:
Brucella sp identified:Prid:Pt:Bld:Nom:Organism specific culture
Bordetella pertussis:PrThr:Pt:Thrt:Ord:Organism specific culture
Chlamydia sp identified:Prid:Pt:Gen:Nom:Organism specific culture
Legionella sp identified:Prid:Pt:Sputum:Nom:Organism specific culture
Note if a test applies to a specific species of organism, the component should include the genus AND
species (at least). If the measure applies to a series of species in the same family the string “sp” must be
included. If it applies to as subgroup of the genus, then that subgroup should be named.
Names for method for general class of organism:
Fungus identified:Prid:Pt:Wound:Nom:Culture
Bacteria identified:Prid:Pt:CSF:Nom:Culture
Again, the Result Value of these tests would be either organism names or other statements of culture
outcome. The table below contains valid values of the culture result from the HL7 OBX segment:
Table 15: Example Culture Results
No growth
Gram-positive cocci
Small Gram negative rod
Escherichia coli
Normal flora
Candida albicans
Presence or Identity (Prid) as a property should be used when the value of a test can identify one set of
alternative infectious agents. If the culture is for herpes virus and the culture can have results of herpes
virus 1, herpes virus 2, etc., then Prid is the right property. If the culture is for herpes virus and the answer
is positive/negative or yes/no, then the property should be presence (PrThr) and the scale ordinal (Ord).
43
3.5 Antimicrobial susceptibilities
The drug susceptibility tests are grouped together in the LOINC database under the class ABXBACT.
Antimicrobial susceptibility tests are named according to the generic name of the drug tested and the
methodology used in testing, with property of susceptibility (Susc), and with scale of quantitative (Qn),
ordinal (Ord), or OrdQn. Thus, appropriate names would be:
Ampicillin:Susc:Pt:Isolate:OrdQn:MIC
Ampicillin:Susc:Pt:Isolate:OrdQn:Agar diffusion
Ticarcillin+Clavulanate:Susc:Pt:Isolate:Qn:MLC
Table 16 lists methods in drug-susceptibility tests.
Table 16: Drug Susceptibility Methods
Method
Description
Agar diffusion
Bacterial sensitivity via agar diffusion (Kirby-Bauer)
MIC
Minimum inhibitory concentration
MLC
Minimum lethal concentration
SBT
Serum bactericidal titer
Gradient strip
Susceptible by E-Test or gradient strip method
Methodless codes also exist for each antimicrobial agent.
3.6 Cell counts
Quantitative counts of various entities and cells in blood, urine, CSF, and other body fluids may be
performed and reported in one of three ways. Cell counts in blood are often reported as absolute counts
per unit volume (property number concentration, NCnc), or percent of a general cell type, e.g., percent
eosinophils, (property number fraction, NFr). Blood cells are usually reported in such a manner, via either
a manual or automated count method. Counts on urine and other body fluids can also be done as direct
counts and reported as NCnc or NFr. However, they are more often reported as the number of entities or
cells per microscopic high power or low power field, e.g., 5-10 cells per high power field. These are
really numbers per area (property Naric). For example, the number of erythrocytes casts per low power
field would be reported as:
Erythrocyte casts:Naric:Pt:Urine sed:Qn:Microscopy.light.LPF
Note that even though the values are reported as a range, the scale is still quantitative (Qn), because the
values can be related through a ratio. We use HPF or LPF to identify high power and low power fields
respectively. Large entities (such as casts) are usually reported per low power fields, smaller entities per
high power fields.
One other way such entities are reported is as a pure ordinal, e.g., none, few, moderate, loaded. These
would be specified as arbitrary concentration (ACnc) properties with ordinal scale, for example:
Erythrocytes:ACnc:Pt:Semen:Ord:Microscopy.light
44
3.7 Skin tests
These follow the pattern of a challenge test. For a TB skin test it would be:
Tuberculosis reaction wheal^3D post 25 TU ID:Diam:Pt:Skin:Qn
Where TU means tuberculin units, ID means intradermal, Diam indicates a measure of the diameter of the
wheal and so on.
3.8 Toxicology – Drug of Abuse Screening and Confirmation
Many kinds of test methods are used in toxicology:
Screening tests include HPLC, EIA, TLC, RIA, GC, and GCMS (rarely).
Confirmation tests are GCMS, LCMS, GC, and HPLC.
Table 17: Drug of Abuse Methods
Abbr.
Description
HPLC
high pressure liquid chromatography
TLC
thin layer chromatography
GC
gas chromatography
EIA
enzyme immunoassay
RIA
Radioimmunoassay
GCMS
gas chromatography/mass spectrometry
LCMS
liquid chromatography/mass spectrometry
Many laboratories use GCMS to signal that the test is a confirmation of a previous screening test, but
other methods are also used to confirm, and a given method can be used to screen or to confirm a test.
However, it is important that two different methods be used for screen and for confirm and that they both
be applied with techniques appropriate to the mode (screen or confirm). So the LOINC committee has
determined it is better to distinguish the screening from the confirming procedure by the use of the words
“screen” or “confirm,” in the method part of the name, rather than by naming a specific method. Hence
LOINC will distinguish toxicology method by Screen and Confirm but not by particular methods.
Toxicology tests can also be performed on a group of drugs/substances or on individual drugs/
metabolites/ substances. We will develop LOINC names and codes for both categories: groups of
analytes, e.g., “barbiturates” and individual analytes, e.g., “phenobarbital.”
Group test results are usually reported as ordinal (present /absent) but can also be reported as mass
concentrations when the numerator is the total mass of the detectable substances in the group. Group tests
at the screening level may also be followed by a confirmation at the group level or by confirms of the
individual drug/substance tests at the confirmatory level. Individual drugs/substances may be reported as
present/absent (Ord) or as mass (or substance) concentrations (Qn).
When individual drugs/substances are reported ordinally, the reporting threshold (the threshold at which a
test level is considered positive) may also be reported as a separate “result.” Thus we have separate
LOINC codes to report the cutoff used for defining a positive or negative value.
45
3.8.1
Toxicology drug groups
General principles: for each “group” of drugs (amphetamines, benzodiazepines, opiates, etc.) we will
define the following kinds of LOINC observations:
3.8.1.1
Screen for a group of drugs/ toxic substances
“X”:PrThr:Pt:Ord:SYS:Screen for the group as a whole
(Answer = present/absent)
For example, Amphetamines:PrThr:Pt:Urine:Ord:Screen
Example answer: “present”
Identify the set of drugs/substances screened for by the group test. The answer will be a list of discrete
drug/substance names or codes.
“X” tested for:Prid:Pt:SYS:Nom:Screen
(Answers = individual drugs that this screening test could detect, from a fixed list)
For example, Amphetamines tested for:Prid:Pt:Urine:Nom:Screen (nominal)
Example answer = “amphetamine, methamphetamine, dextroamphetamine, levoamphetamine, pseudoephedrine”
3.8.1.2
Identify the drugs substances screened for (and perhaps other information). The answer will be a
“glob” of narrative text.
“X” tested for:Prid:Pt:SYS:Nar:Screen
(Answers = individual drugs that this screening test could detect, as a “blob” of text or canned comment)
For example, Amphetamines tested for:Prid:Pt:Urine:Nar:Screen (narrative)
Example answer = “The EMIT urine screen for amphetamines detects amphetamine, methamphetamine, dextroamphetamine,
levoamphetamine as indications of methamphetamine abuse. It is also reactive with a component present in
over-the-counter nasal decongestant inhalers, and a positive result must be confirmed by a quantitative method that
rules out the non-abuse situation”
When a screen is reported as negative, confirmatory testing is not performed. When a screening test is
reported as positive, the result must be confirmed by an independent testing method.
3.8.1.3
Confirmatory testing for the presence of one or more members of the group represented as a
single observation.
“X”:PrThr:Pt:SYS:Ord:Confirm
(Answers = present/absent)
For example, Amphetamines:PrThr:Pt:Urine:Ord:Confirm
3.8.1.4
List of the actual drug/substances confirmed.
“X” positive:Prid:Pt:SYS:Nom:Confirm
(Answers = list of analytes detected)
For example, Amphetamines positive:Prid:Pt:Urine:Nom:Confirm
Example answer: “dextroamphetamine, methamphetamine”
46
3.8.1.5
More commonly, confirmatory testing is reported as a set of observations, one to report
the presence (or quantitative amount detected) of each analyte in the group.
“X”:PrThr:Pt:SYS:Ord:Confirm
(Answers = present/absent)
or
“X”:MCnc:Pt:SYS:Qn:Confirm
(Answers = quantitative amount)
For example:
Amphetamine:PrThr:Pt:Urine:Ord:Confirm [present]
Dextroamphetamine:PrThr:Pt:Urine:Ord:Confirm [present]
Methamphetamine:PrThr:Pt:Urine:Ord:Confirm [present]
Levomethamphetamine:PrThr:Pt:Urine:Ord:Confirm [present]
3.8.2
Cutoffs
The cutoff levels for screens and confirms of a given substance or group of substances will usually differ.
There are three ways to indicate specific cutoffs in LOINC.
3.8.2.1
We provide separate LOINC terms for reporting the cutoff levels of a number of commonly
abused substances and substance groups.
“X” cutoff:MCnc:Pt:Urine:Qn:Screen
“X” cutoff:MCnc:Pt:Urine:Qn:Confirm
For example, Amphetamines cutoff:MCnc:Pt:Urine:Qn:Screen
Example answer: “1000 ng/ml”
For example, Methamphetamine cutoff:MCnc:Pt:Urine:Qn:Confirm
3.8.2.2
Two general cutoff terms, one for screen and one for confirm, can be applied to any substance
whether or not a pre-coordinated term exists.
XXX cutoff:MCnc:Pt:SYS:Qn:Screen
XXX cutoff:MCnc:Pt:SYS:Qn:Confirm
3.8.2.3
For commonly used cutoffs, such as those mandated by regulatory agencies, we provided
precoordinated terms for reporting a “present/absent” result with the cutoff specified in the
method field:
“X”:PrThr:Pt:SYS:Ord:Screen>“N”
“X”:PrThr:Pt:SYS:Ord:Confirm>“N”
For example, Amphetamines:PrThr:Pt:Urine:Ord:Screen>1000 ng/mL
Example answer: “not detected”
3.8.3
Reporting the method used for screen and confirm
We provide terms for reporting the method used for screen and confirm tests:
47
“X” screen method:Prid:Pt:SYS:Nom:*
“X” confirm method:Prid:Pt:SYS:Nom:*
These would normally be reported in conjunction with terms reporting levels and possibly cutoffs, as in
the following example:
Amphetamines:PrThr:Pt:Urine:Ord:Confirm
[Answer = positive]
Amphetamines cutoff:MCnc:Pt:Urine:Qn:Screen
[Answer = 1000 ng/ml]
Amphetamines screen method:Prid:Pt:Urine:Nom:*
[Answer = EIA]
Amphetamines positive:Prid:Pt:Urine:Nom:Confirm
[Answer = amphetamine, methamphetamine]
Amphetamine cutoff:MCnc:Pt:Urine:Qn:Confirm
Methamphetamine cutoff:MCnc:Pt:Urine:Qn:Confirm
Amphetamines confirm method:Prid:Pt:Urine:Nom:*
[Answer = GC/MS]
3.8.4
Individual drug/metabolite test results
Individual substances are typically reported as screens (ordinal), confirms (ordinal) or confirms
(quantitative -- usually mass or substance concentrations), though some labs also report as screen
(quantitative). Ordinal terms for reporting individual substances should always specify a Method of
“screen” or “confirm.”
Group test screens may be confirmed by group confirms (as described above) or by individual confirms
(Either ordinal or quantitative-depending upon the laboratory's preference)
3.8.4.1
Individual test screen (ordinal)
Methamphetamine:PrThr:Pt:Urine:Ord:Screen
3.8.4.2
Individual test screen (quantitative)
Methadone:MCnc:Pt:Urine:Qn:Screen
3.8.4.3
Individual test confirm (ordinal)
Methamphetamine:PrThr:Pt:Urine:Ord:Confirm
3.8.4.4
Individual test confirm (quantitative)
Methamphetamine:MCnc:Pt:Urine:Qn:Confirm
Individual tests may also be reported as simple quantitative (without confirm or screen), as is the case for
48
therapeutic drug level monitoring.
3.8.4.5
Individual substance measured quantitatively; screen/confirm is not relevant
Digoxin:MCnc:Pt:Ser/Plas:Qn
Example answer: “1.2 ng/ml”
3.8.5
Naming issues
For confirms, you would always be looking for specific analytes. For example, you would never look for
tetrahydrocannabinol, but would look for delta-9-tetrahydrocannabinol, 11-hydroxycannabinol, etc.
3.8.6
Summary
For each “group” LOINC defines the following set of terms:
“Analyte group”:PrThr:Pt:Urine:Ord:Screen
“Analyte group”:PrThr:Pt:Urine:Ord:Confirm
“Analyte group”:MCnc:Pt:Urine:Qn:Confirm
“Analyte group” tested for:Prid:Pt:Urine:Nom:Screen
“Analyte group” tested for:Prid:Pt:Urine:Nar:Screen
“Analyte group” positive:Prid:Pt:Urine:Nom:Confirm
“Analyte group” screen method:Prid:Pt:Urine:Nom:*
“Analyte group” confirm method:Prid:Pt:Urine:Nom:*
For each individual analyte LOINC now defines the following set of terms:
Analyte:PrThr:Pt:Urine:Ord:Screen
Analyte:PrThr:Pt:Urine:Ord:Confirm
Analyte:MCnc:Pt:Urine:Qn:Confirm
Analyte:MCnc:Pt:Urine:Qn
Analyte cutoff:MCnc:Pt:Urine:Qn:Screen
Analyte cutoff:MCnc:Pt:Urine:Qn:Confirm
3.9 Molecular Genetics LOINC Naming
3.9.1
Introduction
Molecular pathology testing can be used for many purposes. In infectious disease testing to identify
organisms and mutations in organisms; in genetic analysis to identify mutations including substitutions,
deletions/insertions, frame shifts and trinucleotide repeats; to identify specific chromosomal translocation
and clonality in leukemia and lymphomas; to identify various tumor associated genes and gene deletions;
in paternity testing to determine the probability that a person is the parent of a child; and in forensic
testing to determine the probability that a criminal is associated with genetic material he/she left as
evidence. 25
LOINC term names follow the recommendations and nomenclature of other standards. As molecular
genetic testing expands, we are evolving our naming conventions. Existing terms are being reviewed for
25
Antonarakis, SE, and the Nomenclature Working Group. Recommendations for a nomenclature system for human gene mutations.
Human Mutation 1998;11:1-3.
49
compatibility with current naming conventions. An overall description of LOINC’s approach to naming
molecular genetics tests can be found in the Deckard et al26 paper.
3.9.2
Brief review of molecular genetics terminology
For clarity, here we provide a brief introduction to some key genetics terminology. DNA consists of a
series of nucleotides, nucleotides encode amino acids, and a string of amino acids forms a protein.
There are four types of nucleotides (adenine, guanine, cytosine and thymine), and a sequence of three
nucleotides that codes for one amino acid is called a codon. Codons are numbered from the first codon
participating in the protein (in humans the codon for Methionine) starting with codon number 1. Locus
refers to a specific DNA (or RNA) codon or the corresponding amino acid produced by this codon.
The string of DNA that codes for a protein is usually interrupted by DNA segments called introns, which
do not contribute to the protein definition. The coding sequences of DNA between the introns are called
exons. Linked together, the exons provide the instructions for creating the specific protein. Exons may be
numbered e.g., exon 1, exon 2, etc. Exon numbers sometimes appear in the names of DNA mutations, but
for a number of reasons, identifying codon locations relative to an exon is unreliable and we will try to
avoid such nomenclature when possible in LOINC names.
The term mutation is usually applied to a genetic variant that causes a functional change in the gene and
results in disease. Genetic changes that occur during the life of the patient such as tumor mutation are
called somatic and those that are inherited are referred to as germ line. The nature of the specimen and
the testing usually distinguishes these two, so it is not necessary to include this distinction in the test
names.
Alleles refer to different forms of a gene and are distinguished at the phenotype level. The term allele is
usually applied to a genetic variant that does not cause a disease.
3.9.3
Background on molecular genetics testing methods
The main laboratory methods used are Southern Blot, which applies hybridization to selected DNA
“chopped up” by restriction enzymes, Northern Blot, which applies hybridization to all cellular RNA
(which comes naturally in smaller segments) and Restriction Fragment Length Polymorphism (RFLP).
RFLP depends on the Variable Number of Tandem Repeats (VNTR), which are normal, but specific
variants of each person’s DNA. Southern Blot may be combined with RFLP to target mutations whose
exact gene molecular chemistry is not known. For completeness sake, we mention Western Blot, which
applies an analogous blot method to protein analysis.
In situ hybridization is a method that applies probes to intact tissue. The cellular patterns of the
homologies can then be read microscopically. There are a variety of methods for detecting such in situ
probes. One popular method is Fluorescent In-Situ Hybridization (FISH). This technique is analogous to
an immune stain except that the molecular binding is based on DNA/RNA homologies instead of antigenantibody binding.
DNA chips provide a radical new way to identify DNA and RNA sequences. In the patented
AFYMETRIX® technique, the nucleoside chains are grown using lithography-like methods. Target DNA
26
Deckard J, McDonald CJ, Vreeman DJ. Supporting interoperability of genetic data with LOINC. J Am Med Inform Assoc. 2015
May;22(3):621-7. PubMed PMID: 25656513.
50
is tagged with a detector and “washed” over the chip in steps. The locations of the tags on the chip
identify the DNA (RNA) in the sample.
Identity testing is used to identify relationships among people and has special complexity. In paternity
testing, it can be helpful to have DNA from the child, the putative father and the mother when possible to
distinguish the alleles that come from the father.
Forensic testing has special requirements of stringency and often mixes blood antigen testing with RFLP
testing. The results are usually reported as a probability.
3.9.4
General molecular genetics naming rules
LOINC’s approach to naming tests makes use of established conventions. For naming genetic tests that
target specific genetic variations, LOINC uses the Human Genome Organization (HUGO) Gene
Nomenclature Committee's (HGNC) terminology to name the gene(s) and Human Genome Variation
Society's (HGVS, http://www.hgvs.org/mutnomen/) syntax to name the variation(s) of interest.
HGVS provides four different levels of naming gene defects as described in Table 18.
Table 18: Four types of nomenclatures for identifying the location of a genetic defect
Designation
p
c
g
m
Explanation
Identify the defect by codon by counting the amino acids in the protein produced by the gene counting the first amino acid.
Identify the defect by counting nucleotides from the messenger RNA used to produce the protein with introns excluded.
Since three nucleotides = one codon, these will produce numbers 3x as large as those in the first method.
Identify the defect by counting from the first nucleotide in the DNA for the gene of interest, as it exists natively in the
chromosome with introns included.
Identify the defect by counting from the first nucleotide in the full mitochondrial DNA sequence.
The HGVS recommendations have evolved over time. In our early approach, we used the extant proteinbased naming convention to get the following name for the commonest mutation causing cystic fibrosis:
CFTR gene.p.F508del:PrThr:Pt:Bld/Tiss:Ord:Molgen
For clarity’s sake, HGVS now prefers the three letter amino acid abbreviations over the single letter
amino acid abbreviations we used in the above example.
We embrace the HGVS naming style for naming mutations at the amino acid level, but the world has not
been consistently quick to adopt it. The old style, perhaps because of its brevity, persists. As we update
existing codes to harmonize with current HGVS guidelines, we will make it easy for users to find our test
names by including the old style as synonyms for the new style. Under the current HGVS rules, the above
name would be:
CFTR gene.p.Phe508del:PrThr:Pt:Bld/Tiss:Ord:Molgen
Where we still report variants at the amino acid level, we use the nomenclature for human gene mutations
proposed by Beaudet27 in the component or in the answer when the mutation is reported as an answer. A
list of single and three letter amino acid codes are given in Table 19.
27
Beaudet AL, Tsui LC. A suggested nomenclature for designating mutations. Human Mutation 1993;2:245-248.
51
Table 19: List of single letter amino acid codes
Amino Acid
1-Letter Symbol
3-Letter Symbol
Alanine
A
Ala
Arginine
R
Arg
Asparagine
N
Asn
Aspartic acid
D
Asp
Cysteine
C
Cys
Glutamic acid
E
Glu
Glutamine
Q
Gln
Pyroglutamic acid
pQ
pGlu
Glycine
G
Gly
Histidine
H
His
Hydroxyproline, 4(R)-L-
O
Hyp
Isoleucine
I
Ile
Leucine
L
Leu
Lysine
K
Lys
Methionine
M
Met
Phenylalanine
F
Phe
Proline
P
Pro
Serine
S
Ser
Threonine
T
Thr
Tryptophan
W
Trp
Tyrosine
Y
Tyr
Valine
V
Val
Unknown
X
HGVS has made other changes in naming style. Overall they now prefer describing the variant at the
coding DNA level as nucleotide changes rather than at the protein level as amino acid changes. The above
cystic fibrosis mutation would have the following coding DNA-based name:
CFTR gene.c.1521_1523del:PrThr:Pt:Bld/Tiss:Ord:Molgen
For the nucleotide changes, they have adjusted the syntax for representing a change from one nucleotide
string to another as # String1>String2 rather than String1 # String2, where # is an integer representing the
nucleotide position of the variation.
Another common cause of cystic fibrosis is a mutation that at the amino acid level would be named
p.Gly551Asp with the new protein based naming convention, c.G1652A with the old DNA naming
convention and c.1652G>A with the new coding DNA naming convention. (Realize, of course, that more
than one nucleotide-level variation name can correspond to a single amino acid variation name).
If clear guidelines are not in place for a given variant when a LOINC code is created, the familiar or
common variant name may be used. LOINC will resort to using the disease name only when the gene has
no name and/or the genetic defect is not yet fully specified. We will always include the genetic disease
name in the related name field of the database when the disease name is not part of the component. This
allows users to easily find the LOINC term by the disease name as well.
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3.9.4.1
Specimens in molecular genetics
Blood is the most common specimen for molecular pathology studies. Leukocytes, bone marrow, tumors,
products of conception and forensic specimens also contain DNA and are important specimens. The
system (specimen) used in the LOINC name for genetic testing will usually be Bld/Tiss since the
distinction between these two specimens is rarely important to the result of a molecular pathology test.
We have split this further to accommodate fetal specimens (Tiss^fetus). Other specimens include
amniotic fluid, CVS, bone marrow, fixed tissue, and CSF.
3.9.4.2
Methods in molecular genetics
In general, we do not create separate variables for each kind of molecular genetics method, (e.g., Southern
Blot Northern Blot, PCR, restriction fragment length polymorphism (RFLP)) because the different
methods do not provide significantly different results. Moreover, there are a plethora of minor method
variants, and we would not be able to keep up with their proliferation. Therefore, instead we use a generic
method of Molgen (for molecular genetics method) to indicate that a result of the analysis is based on a
molecular genetics method rather than some chemical or antigen method.
However, when results for a given molecular pathology technique are significantly different, we will
distinguish the method. Examples of specific molecular pathology methods in LOINC include fluorescent
in situ hybridization (FISH), sequencing, multiplex ligation probe amplification (MLPA), and microarray
comparative genomic hybridization (arrCGH).
3.9.4.3
Narrative and document-level reporting in molecular genetics
Bulk narrative reports in molecular pathology are often used to provide results for mutation analyses,
without reporting any discrete coded answers. We discourage the use of this approach because it is not
useful for automated analyses. Since these kinds of results often include some structured elements, we
will use the Property “Find” and Scale “Doc” beginning with version 2.54. The scale of “Doc” represents
a collection of information (e.g. results contained in a report) that are either structured or unstructured. To
assist with structured reporting, we will attach to these terms specific associated observations that could
be used to send data in a structured format. With this approach, labs will still have the flexibility to send
text reports. However, we encourage them to also report key data as structured results using the associated
observation variables so that it is more easily understood by computers. We plan to use this model for
newly created terms for molecular pathology tests and, are contemplating the best approach for
transitioning existing terms to this format over time.
3.9.5
Infectious diseases
For most infections disease reporting, the existing LOINC nomenclature (e.g., detecting a particular
species of organism by detecting DNA homology) works fine. The word DNA or RNA is included as part
of the component name and we distinguish the type of method used for detecting the microorganisms
(Probe, Probe.amp.tar, Non-probe.amp.tar, Probe.amp.sig). See the Microbiology section for more
information.
53
3.9.6
3.9.6.1
Genetic conditions
Diagnostic assays for the detection of specific mutations or variants
We currently have at least four different styles for mutation analyses in LOINC:
1) Single mutation analysis: Diagnostic assays for the detection of a specific mutation or variant
2) Targeted mutation analysis: Diagnostic assays for a fixed set of the most common or
important mutations
3) Known mutation analysis: Diagnostic assays for one or more mutations that have been
previously identified in an affected family member
4) Full gene mutation analysis: Diagnostic assays usually done by sequencing of the entire
coding region of a gene
3.9.6.1.1 Diagnostic assays for the detection of a specific mutation or variant
When looking for one mutation, use LOINC’s single mutation style of gene name followed by the
specification of the nomenclature (p, g, c, or m) and the mutation name. A dot will separate the gene
name and the mutation identifier:
<gene name> gene.<mutation nomenclature>.<mutation and its location>
For example, Factor V Leiden mutation would be represented as F5 gene.p.R506Q. Where “F5” identifies
the gene, “gene” is a fixed part, “p” identifies the kind of mutation nomenclature (protein) and “R506Q”
indicates that the amino acid arginine (R) is replaced by glutamine (Q) (see Table 19) at codon #506.
Some examples of fully specified LOINC names for tests of specific mutation are:
F5 gene.p.R506Q: PrThr :Pt:Bld/Tiss:Ord:Molgen
Synonyms = Factor V Leiden, Factor V resistance, APC resistance gene
HFE gene.p.C282Y: PrThr :Pt:Bld/Tiss:Ord:Molgen
Synonyms = HLA-H gene, hemochromatosis gene
CFTR gene.p.F508 del:PrThr:Pt:Bld/Tiss:Ord:Molgen
Synonyms = Cystic Fibrosis Transmembrane Regulator
As mentioned above, HGVS now recommends the three letter amino acid abbreviations over the single
letter amino acid abbreviations. As existing codes are updated, we will add synonyms for the old style to
make it easy for users to find our test names.
One type of testing procedure identifies a single mutation using two DNA probes: one for the normal
locus and the other for the abnormal locus. When only the normal probe reacts, the laboratory reports “no
mutation” or “wild type”. When both the normal and mutation probes react, the laboratory reports
“heterozygous”. When only the mutation probe reacts it reports “homozygous”. Consequently, such
single mutation testing produces one of three ordinal “answers”:
a) no mutation (wild type)
b) heterozygous mutation (the mutation found in one gene)
54
c) homozygous mutation (the mutation was found in both genes in the gene pair)
Specific testing such as this is only possible when the molecular pathology of the gene is very well known
and only one defect is being reported.
Both document-level (scale is Doc) and ordinal (scale is Ord) codes are available in the LOINC database
for single variant tests. In cases where more than one variant is tested, a nominal scale will be used. As
mentioned above, we encourage the use of document-level codes for the order and overall result report,
which can be used in conjunction with additional LOINC codes for reporting the discrete results.
Results for specific mutations or variants may also be reported as two separate observations: one
observation reports the kind of mutation (allele) found in the first chromosome and another for reporting
the kind of mutation for the paired chromosome. In this case, the identity of the allele is reported in the
answer. For example:
APOE gene allele 1:Prid:Pt:Bld/Tiss:Nom:Molgen
Answers = E2, E3, or E4
APOE gene allele 2:Prid:Pt:Bld/Tiss:Nom:Molgen
Answers = E2, E3, or E4
3.9.6.1.2 Targeted mutation analysis
LOINC’s approach to represent gene mutation analysis for many genetic variations within one or more
genes has had the following form:
<gene or disease name> targeted gene mutation analysis:Find;Pt:Bld/Tiss:Doc:Molgen
For example:
CFTR gene mutation analysis:Find:Pt:Bld/Tiss:Doc:Molgen
Synonyms = Cystic fibrosis transmembrane regulator
BRCA1 gene mutation analysis:Find:Pt:Bld/Tiss:Doc:Molgen
Synonyms = breast cancer risk gene
For each such targeted mutation analysis, we recommend reporting the mutations that were tested using
an additional LOINC code, such as LOINC 36908-2 (Gene mutations tested for) or gene-specific
companion LOINC observation codes with the words “mutations tested for”:
<Gene or disease name> gene mutations tested for:Prid:Pt:Bld/Tiss:Nom:Molgen
For example:
CFTR gene mutations tested for:Prid:Pt:Bld/Tiss:Nom:Molgen
The answers could include “Delta F508”, “G542X”, “R553X”, “W1282X”, “N1303K”, etc.
The additional LOINC code is needed for reporting the mutation(s) that could have been found in a given
analysis so that clinicians can know what was looked for when no abnormalities were found.
The above gene mutation analysis terms could be used for ordering or reporting the results of a given
targeted mutation analysis. Both document-level (scale is Doc) and nominal (scale is Nom) codes are
available in the LOINC database. As mentioned above, we encourage the use of document-level codes for
the order and overall result report, which can be used in conjunction with additional LOINC codes for
55
reporting the discrete results. Nominal results for such analyses could be: 1) no pathologic mutations
found or 2) a list of individual mutations/variations found. When reporting discrete mutations as results,
we propose using the HGVS nomenclature and including (in parentheses) the historic versions of the
mutation names when such names exist.
3.9.6.1.3 Known mutation analysis
The first two approaches are commonly called “targeted” mutation analyses, or looking for specific
mutations within a given gene. Labs may offer testing for both targeted mutation analysis and analysis for
known familial mutations. Known familial mutations are those previously identified within an affected
family member. To distinguish these testing approaches, LOINC further defines testing for known
familial mutations:
<Gene name> gene mutation analysis limited to known familial mutations:Find:Pt:Bld/Tiss:Doc:Molgen
For example:
TNFRSF13B gene mutation analysis limited to known familial mutations:Find:Pt:Bld/Tiss:Doc:Molgen
Since testing may involve more than one known mutation, especially for autosomal recessive conditions,
LOINC uses the plural form of mutations in the Component. However, these terms also refer to testing for
only one known familial mutation.
3.9.6.1.4 Full gene mutation analysis
To describe mutation analysis by sequencing of the entire coding region of the gene, we use:
TNFRSF13B gene full mutation analysis:Find:Pt:Bld/Tiss:Doc:Sequencing
Here, we include the method of sequencing since this is a technique commonly used to identify mutations
with the entire coding region of a gene.
3.9.6.2
Diagnostic assays for large deletions and/or duplications
Detection of larger (>50 bp) genomic duplications or deletions is done by various techniques, including
multiplex ligation-dependent probe amplifications (MLPA) and array-based comparative genomic
hybridization (arrCGH). MLPA and aarCGH techniques detect gene dosage. To describe testing for large
deletions and/or duplications (insertions) within a gene, we use:
LDLR gene deletion+duplication:Prid:Pt:Bld/Tiss:Nar:MLPA
In this case, we specify the method of multiplex ligation-dependent probe amplification (MLPA). MLPA
is a common technique used to detect gene dosage of genomic deletions and duplications (e.g. one or
more entire exons) and determine gene copy number.
3.9.6.3
Trinucleotide repeats
A number of diseases, most of which manifest as neurologic disorders are caused by excessive repeats of
56
specific trinucleotides, and the age of onset of the disease is inversely proportional to the number of
excess repeats. Examples of these disorders include:
Fragile X syndrome
Huntington disease
Spinocerebellar ataxia (SCA1)
We name the component of these terms by the gene when the gene is well defined or the disease, and the
name of the trinucleotide that repeats plus the word “repeats”.
<disease or gene name>.<trinucleotide> repeats
For example, Huntington disease would be represented as HTT gene.CAG repeats
Examples of some fully specified LOINC names are:
FRAXE gene.CGG repeats:PrThr:Pt:Bld/Tiss:Ord:Molgen
Synonym = Fragile x syndrome
HTT gene.CAG repeats:PrThr:Pt:Bld/Tiss:Ord:Molgen
Synonym = Huntington Disease, It15, HD, Huntington Chorea
Spinocerebellar ataxia genes.CAG repeats:PrThr:Pt:Bld/Tiss:Ord:Molgen
DMPK gene.CTG repeats:PrThr:Pt:Bld/Tiss:Ord:Molgen
Synonym = Myotonic Dystrophy
These are usually reported “not expanded”, “indeterminate” or “expanded”, so the scale is Ord.
When the actual number of trinucleotide repeats is reported, the property is entitic number (EntNum) and
the scale is quantitative (Qn), and separate results are reported for each allele. Examples include:
HTT gene allele 1.CAG repeats:EntNum:Pt:Bld/Tiss:Qn:Molgen
HTT gene allele 2.CAG repeats:EntNum:Pt:Bld/Tiss:Qn:Molgen
DMPK gene allele 1.CTG repeats:EntNum:Pt:Bld/Tiss:Qn:Molgen
DMPK gene allele 2.CTG repeats:EntNum:Pt:Bld/Tiss:Qn:Molgen
3.9.6.4
Hematopathology gene re-arrangement.
Immune cells have an innate genetic variability due to rearrangement. The unique rearrangement can be
used to identify the development of a clone of one cell type as occurs in many lymph cell tumors (e.g.,
lymphoma). We use the following format to identify clonal excess.
Immunoglobulin heavy chain gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Immunoglobulin kappa light chain gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Immunoglobulin lambda light chain gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
TCRB gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonym = T cell receptor beta chain
TCRD gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonym = T cell receptor delta chain
TCRG gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonym = T cell receptor gamma chain
57
These would be reported as “clonal” or “not clonal”.
3.9.6.5
Chromosomal alterations: translocations, deletions, and inversions
LOINC nomenclature follows the International System for Human Cytogenetic Nomenclature (ISCN)
guidelines when describing chromosomal alterations, including translocations, large deletions and
inversions. Tests to detect fused genes or transcripts (RNA, cDNA) due to a chromosomal alteration are
designated as follows:
t(<Chromosome of breakpoint gene 1>;<Chromosome of breakpoint gene 2>)(<Location on chromosome 1>; <Location on
chromosome 2)(<gene1>,<gene2>) fusion transcript
For example:
t(9;22)(q34.1;q11)(ABL1,BCR) fusion transcript:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = Philadelphia chromosome, BCR1, chronic myeloid leukemia, CML
t(14;18)(q32;q21.3)(IGH,BCL2) fusion transcript:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = Follicular B cell lymphoma, oncogene B-cell leukemia 2, CLL, chronic lymphatic leukemia, follicular
lymphoma
t(15;17)(q24.1;q21.1)(PML,RARA) fusion transcript:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = RAR, promyelocytic leukemia, myelogenous, retinoic acid receptor, acute promyelocytic leukemia, APL
For chromosomal deletions and inversion,‘t’ above would be replace with ‘del’ or ‘inv’, respectively:
del(1)(p32p32)(STIL,TAL1) fusion transcript:PrThr:Pt:Bld/Tiss:Ord:Molgen
Synonyms = SCL/TAL1 interrupting locus, T-cell acute lymphoblastic leukemia, ALL, T-ALL, TAL-1 deletions
inv(16)(p13.1;q22.1)(MYH11,CBFB) fusion transcript:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = inversion 16, AML, Acute myeloid leukemia
In some cases, testing may involve comparing the fused transcript to a control transcript and results may
be reported as a number ratio (NRto), log number ratio (LnRto), or relative ratio (RelRto):
t(9;22)(q34.1;q11)(ABL1,BCR) fusion transcript/control transcript:NRto:Pt:Bld/Tiss:Ord:Molgen
t(9;22)(q34.1;q11)(ABL1,BCR) fusion transcript/control transcript:LnRto:Pt:Bld/Tiss:Ord:Molgen
t(9;22)(q34.1;q11)(ABL1,BCR) b3a2 fusion transcript/control transcript (International Scale):RelRto:Pt:Bld/Tiss:Ord:Molgen
To specify “major” or “minor” breakpoints, we use:
t(9;22)(q34.1;q11)(ABL1,BCR) fusion transcript major break points:Arb:Pt:Bld/Tiss:Ord:Molgen
t(9;22)(q34.1;q11)(ABL1,BCR) fusion transcript minor break points:Arb:Pt:Bld/Tiss:Ord:Molgen
To specify specific breakpoints, we use:
t(9;22)(q34.1;q11)(ABL1,BCR) b2a2+b3a2 fusion transcript:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = major breakpoints, p210, e13a2, e14a2,
t(15;17)(q24.1;q21.1)(PML,RARA) bcr1 fusion transcript:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = breakpoint cluster region 1, long form
58
Translocation terms can also be expressed as a fraction of cells that have the rearrangement versus total
cells of interest:
Cells.t(9;22)(q34.1;q11)(ABL1,BCR)/Cells.total:NFr:Pt:Bld/Tiss:Qn:Molgen
If specific partner genes are not known, we use the pattern:
CCND1 gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = Lymphoma 1
BCL2 gene rearrangements:Arb:Pt:Bld/Tiss:Ord:Molgen
Synonyms = Lymphoma 2
3.9.7
Identity testing
The identity testers usually look at 4 genetic loci (each locus is polymorphic enough that any one match
has a 10% error of being incorrect). The loci are independent so if all 4 probes match (including all
exclusions and inclusions) the probability of an erroneously match is .0001 (one out of 10,000). They may
use more than four depending upon the degree of confidence required by the circumstances of the testing.
The forensic community chooses from a set of about 20 probes.
We propose two styles for reporting identity testing: atomic and pre-coordinated definitions.
3.9.7.1
Atomic style
This style uses a series of LOINC names to report the kind of index case, the kind of comparison case, the
results of the identity testing, and all of the other separate components of the testing. It includes an
observation for reporting the actual probes used, and another observation for reporting the population that
the probes assume. The method will be MOLGEN.IDENTITY.TESTING. For example:
DNA probes used:Prid:Pt:Index case^comparison case:Nom: Molgen.identity.testing
Population base:Prid:Pt:Probes:Nom: Molgen.identity.testing
Relationship:Type:Pt:index case:Nom: Molgen.identity.testing
Answers = child, victim, suspect
Relationship:Type:Pt:^comparison case:Nom: Molgen.identity.testing
Answers = mother, alleged mother, father, alleged father, evidence
(external to victim)
Confidence of relationship:likelihood:Pt:Index case^comparison case:QN: Molgen.identity.testing
(gives the statistical confidence in the conclusion)
Conclusion:Imp:Pt:index case^comparison case:Nar: Molgen.identity.testing
(gives a summary statement of the conclusion about identity of relatedness)
3.9.7.2
Pre-coordinated definitions alternative
Some of the above atomic terms (e.g., DNA probes used) could also be reported with the pre-coordinated
results.
Relationship:likelihood: childâlleged mother:Qn:Molgen.identity.testing
Synonyms= maternity testing
59
(gives the likelihood that the alleged mother is the mother of the index child)
Relationship:likelihood:childâlleged father:Qn:Molgen.identity.testing
Synonyms = paternity testing
(gives the likelihood that the alleged father is the father of the index child)
Relationship:likelihood: victim^suspect:Qn:Molgen.identity.testing
(gives the likelihood that the genetic material on the victim is that of the suspect)
Relationship:likelihood: suspect^victim:Qn:Molgen.identity.testing
(gives the likelihood that the genetic material on the suspect is that of the victim)
Identity:likelihood:Evidence^suspect:Qn:Molgen.identity.testing
(gives the likelihood that the genetic material on the evidence is that of the suspect)
Identity:likelihood:evidence^victim:Qn:Molgen.identity.testing
(gives the likelihood that the genetic material on the evidence is that of the victim)
Tumor related genetics
Using the models described in this section, LOINC has terms for many genetic tests relevant to cancer,
including tests related to tumor suppressor genes (e.g. BRCA1, BRCA2, and p53), oncogenes (e.g.
HER2), and more.
3.10 HLA allele and antigen nomenclature
Naming conventions for HLA alleles and antigens are specified by the WHO Nomenclature Committee
for Factors of the HLA System. Recommendations for both allele and antigen naming have evolved since
the original HLA terms were represented in LOINC. For the LOINC 2.54 release (December 2015), we
updated nearly all of the antigen and allele terms to reflect the WHO Nomenclature Committee’s latest
recommendations. HLA allele and antigen naming conventions are briefly described below; for more
details, see http://hla.alleles.org/.
Allele names begin with the “HLA-” prefix and gene name, followed by an asterisk (e.g. “HLA-A* or
HLA-DR*”) and up to four sets of numbers separated by colons. The first set of digits following the
asterisk describes the allele type, which may correspond to the serological antigen number (e.g., “HLAA*01 corresponds to the antigen HLA-A1). The second set of digits is the subtype number, which is
assigned in the order in which the subtype was identified and sequenced. The third and fourth sets of
digits describe the specific sequence variations of the subtype if applicable.
Antigen names also begin with the “HLA-“ prefix and specific gene, but antigen names are distinguished
from allele names in that the gene name is not followed by an asterisk. For HLA-A, -B, -DQ and –DR, the
antigen number immediately follows the gene name, and HLA-C, -D and -DP have a lower case w
between the gene name and the antigen number (e.g., HLA-Cw3). The lower case w is used to distinguish
the C antigens from complement factors and the D and DP antigens as being identified by cellular
techniques rather than serological ones. Most antigen names have one set of digits (the antigen number)
following the gene name, but in some cases, if an antigen originally identified as a single antigen was
later recognized as being two distinct entities, the original, broader antigen number will follow the
specific number in parentheses. For example, HLA-B38(16) and HLA-B39(16).
3.11 Allergy Testing
The allergy testing industry provides tests for more than 450 different allergens today. Most testing
detects IgE antibodies against these allergens. For some allergens testing for IgG and IgA antibodies are
available, as well.
60
For LOINC terms that represent allergen testing, the component is the allergen name plus the type of the
antibody (mostly IgE). Most allergens relate to animals, plants or derivatives of such entities. In the past
(prior to LOINC vs. 2.04), we used the common name, rather than the scientific name to identify the
allergen. However, this approach led to some duplicate term definitions, because two different companies
would name the same allergen differently. It also led to ambiguity because two different species of animal
or plant would sometimes have the same common name. As of version 2.04, we corrected these problems.
To help reduce the ambiguity we now use the Latin name of the species of the biologic entity that causes
the allergy.
Some background: First, most allergens can also be identified with a special 2-5 character code assigned
by Pharmacia28 that most allergy testing companies reference in their catalogue of testing. We used these
codes to identify duplicate and ambiguous LOINC allergy test terms. These Pharmacia codes are also
included in the related names field of the database. Second, allergen tests are often reported in two styles:
a quantitative raw measure and an ordinal (0-6) severity rank (RAST class). LOINC defines separate
terms for each of these reporting styles. For example, the two LOINC codes for reporting IgE antibodies
to Japanese Millet are:
Echinochloa crus-galli Ab.IgE:ACnc:Pt:Ser:Qn
Echinochloa crus-galli Ab.IgE.RAST class:ACnc:Pt:Ser:Ord
The RAST class is a categorization of the raw measurement based on specific allergy criteria. The
specific IgE class result values (0, 1, 2, 3, 4, 5, or 6) are an ordered categorical response rather than a
continuous numeric scale, therefore “RAST class” terms have an ordinal (ORD) scale.
Laboratories also test mixtures of allergens to produce one result. These will be represented in LOINC as
follows:
(Acer negundo+Quercus alba+Ulmus americana+Populus deltoides+Carya pecan) Ab.IgE:ACnc:Pt:Ser:Ord:Multidisk
Related name = tx2
There may be more than one type of allergen for each plant. For instance, IgE antibodies can develop
towards tree pollen and the fruit of the same tree. Similarly, antibodies exist for grain and for grain pollen.
In these cases, the LOINC component will contain the word “POLLEN” to distinguish the pollen allergen
from the food allergen. For example, the LOINC term for corn (maize) IgE antibody would be:
Zea mays Ab.IgE:ACnc:Pt:Ser:Qn:
Related names = f8; cultivated corn; maize
Zea mays pollen Ab.IgE:ACnc:Pt:Ser:Qn
Related names: g202: cultivated corn; maize
Naming rules for allergens
The component (analyte) for an allergen consists of the name of the biologic organism that is the source
of the allergen. The formal name will use the Latin taxonomic name e.g. Arachis hypogaea. The long
common name will use the common name of that entity, e.g. Peanut, if one exists.
In the case of very well specified allergens, the component will also indicate whether the allergen has a
natural source or has been generated via recombinant method by adding the word, "native" or
"recombinant, respectively. Different antigens from the same species are distinguished by the addition of
a sequence number that roughly reflects when in time they were identified.
28
ImmunoCAP Allergens [Internet]. Uppsala(Sweden): ImmunoCAP; c2006 [updated 2007 November 2; cited 2008 June]. Available
from: http://www.immunocapinvitrosight.com/ .
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So you will see names that contain content like :
Arachis hypogaea recombinant 1
Arachis hypogaea recombinant 3
Arachis hypogaea native 1
Arachis hypogaea native 3
However, as is true in other classes of LOINC, we sometimes embed synonyms within the allergen
analyte name to help users recognize the term by their naming rules. Using the LOINC wide convention,
synonyms are enclosed in parentheses and immediately follow the word or words which they represent.
We insert standard acronym names used by most allergen manufacturers as synonyms. These begin with
lower case "n" or "r" to distinguish native from recombinant allergens followed by the first 3 letters of the
genus (in Latin), a space and the first letter of the species (in Latin). If the first 3 letters of the genus and
the first letter of the species are not enough to distinguish between two allergens, the second letter of the
species name is added (e.g., Prunus avium recombinant (rPru av) 1). Because the content in the
parentheses represents the antigen acronym and not the Pharmacia code, the antigen sequence number is
purposely placed after the closed parenthesis. Of course we also append Ab.IgE to the end of this entity
name.
Putting this all together formal and common name for the component for the allergens listed above
become:
LOINC code
58779-0
58777-4
65769-2
65771-8
4
Formal name of component
Arachis hypogaea recombinant (rAra h) 1 Ab.IgE
Arachis hypogaea recombinant (rAra h) 3 Ab.IgE
Arachis hypogaea native (nAra h) 1 Ab.IgE
Arachis hypogaea native (nAra h) 3 Ab.IgE
Long common name of component
Peanut recombinant (rAra h) 1 IgE Ab
Peanut recombinant (rAra h) 3 IgE Ab
Peanut native (nAra h) 1 IgE Ab
Peanut native (nAra h) 3 IgE Ab
Clinical observations and measures
4.1 Introduction
For most of the measures we include separate observations for summary data, e.g., shift and 24-hour urine
output totals. We also provide varying degrees of pre-coordination for the observation, the body site at
which it was obtained, and the method. For example, a cardiac output based on the Fick method is
distinguished from a cardiac output computed from 2D cardiac echo data.
Physiologic measures are often monitored continuously over time and the instrument reports summary
“statistics” over that reporting period. For vital signs these can include minimum, maximum, and mean
value over a time period. For intake and output the total is the summary statistic usually reported. When
we address measures taken over time, we usually include 1 hour, 8 hour, 10 hour, 12 hour, and 24 hour
intervals to cover the varying lengths of work shifts within and across institutions. The LOINC names of
these correspond to the form of a 24-hour urine specimen. The times are recorded in the duration (third
part) of the name.
The parts of clinical measurement names are largely the same as for laboratory measures, with some
subtle differences that are detailed below.
Parts 2, 3, 5 and 6 (type of property, timing, scale, and method) correspond exactly in meaning between
62
laboratory and clinical LOINC codes.
System: Part 4, body system, has the same general meaning for clinical and laboratory measures, but
whereas in the case of laboratory tests the system usually identifies a fluid and a body compartment by
implication (e.g., serum, cerebral spinal fluid), for clinical terms, the system is usually a body part (e.g.,
chest), organ (e.g., heart), or part of an organ (e.g., heart.ventricle). In some cases the system may be an
instrument or device attached to the system (e.g., OB ultrasound imaging device).
Component: In the case of laboratory test observations, the component (part 1) usually identifies some
chemical moiety that is distributed in the system (glucose, or HIV antibodies). In the case of clinical
terms, the component usually identifies a particular projection of a three or four dimension space to a
measure of a particular feature (e.g., QRS interval, systolic) of a time changing measure
(ventricle.left.outflow tract). In addition, the component is used to distinguish the various ranges or
inflections of a physiologic tracing, or to define precisely the section in three-dimensional space in which
an area or range is being measured.
The component includes such things as the special kinds of length (e.g., circumference, diameter, or
radius) when length is the property, and the specific level and axis on which a measurement of a body part
is taken, e.g., circumference taken at the nipple line. The component should remove all ambiguity as to
what projection or axis or specific sub-time frame is being measured. So if one is measuring the diameter
of the kidney, the system would have to specify kidney.right (or kidney.left), and the component would
identify the axis and level at which the diameter was measured (e.g., cross-sectional at level of pelvis).
For a measure of chest circumference the system = chest, the component = circumference at nipple line,
and the property = length. Areas, lengths, and volumes of organs all have to be specified enough in the
component to distinguish a particular area or length that is being measured. When a measure changes over
some cycle (e.g., inspiration, expiration, diastole, and systole), then that should also be specified in the
component. (Duration is used to identify the duration of an overall study.)
For most clinical measurements, the component is an attribute of a patient or an organ system within a
patient. However, attributes of non-patient systems are also often of interest. For example, we might want
to know the class of instrument used to obtain the measurement: i.e., the vendor model number or
institutional inventory number of an endoscopy. Such identification numbers have a property of ID.
Infection control might want the latter reported in order to track nosocomial infections.
When attributes of an instrument or device are being reported, the system is the name of the instrument.
The same is true when we report characteristics of tubes used to move fluid in and out of body cavities.
For example, we might want to report the size and type of a nasogastric tube.
Table 20: Example subjects covered in clinical LOINC
Body pressure (systolic, diastolic, and mean)
Body measurements
Body weight (and measures used to estimate ideal body weight)
Cardiac ultrasound
Cardiac output, resistance, stroke work, ejection, fraction, etc.
Circumference of chest, thighs, legs
Critical care measures
Dental
Electrocardiographic measures
63
Emergency department case reports (CDC DEEDS)
Gastroenterology endoscopy
Heart rate (and character of the pulse wave)
Intake and output
Major headings in operative note
Major headings in discharge summary
Major headings of history and physical
Obstetric ultrasound imaging
Ophthalmology measurements
Pathology protocols
Pulmonary ventilator management
Radiology reports
Respiratory rate
Standardization survey instruments
Urology ultrasound imaging
To accommodate the special dimensions of clinical observations we have introduced new options for the
kind of property. The new kinds of property are what you might expect from the new kinds of dimensions
being measured (e.g., resistance, voltage, work per beat). However, we have also introduced three
important new properties:
Anat
Anatomic is a special case of Prid that identifies anatomic sites.
Imp
Impression is a diagnostic statement, always an interpretation or abstraction of some
other observation (a series of test results, an image, or a total patient), and almost always
generated by a professional. (We could also consider the EKG cart's automated diagnoses
as impressions.) Impressions are used in laboratory medicine as well as clinical
medicine, so you will see them appearing there as well.
Find
Finding is an atomic clinical observation, not a summary statement as an impression.
Physical, review of systems and other such observations have a property of Finding.
These may have a scale of Nom for coded findings, Nar for findings reported in narrative
text or Ord for ordinal findings.
Hx
Terms representing patient or family history concepts originally had Components that
began with “History of” and were assigned the Find property. As of LOINC version 2.56,
these terms were updated to remove “History of” from the Component and change the
Property to Hx, which is exactly what this Property represents.
In clinical measures, super systems (the second subpart of the system component) may be required. For
example, we distinguish head measures of a patient versus a fetus as follows:
Circumference.occipital-frontal:Len:Pt:Head:Qn
Diameter.biparietal:Len:Pt:Head^fetus:Qn
4.2 Atomic versus molecular (pre-coordinated names)
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With clinical terms we almost always have two ways of reporting. Using the first, we can report an
observation by reporting a number of atomic variables which together fully describe the observation. For
example, we have the following atomic observations for circumference measures. These variables let us
deal with all of the unique kinds of circumferences for which we have not yet defined a pre-coordinated
term.
Table 21: Examples of Pre-Coordinated Names
Code
Description
Circumference:Len:Pt:XXX:Qn
The actual measure of some circumference
Identifies the body part measured
(specifies the system)
Identifies the measuring technique used to obtain
the circumference
(answers = tape measure, derived, imaging)
Circumference site:Anat:Pt:*:Nom
Circumference method:Type:Pt:XXX:Nom:*
We also provide pre-coordinated terms that combine some of the atomic variables into one LOINC code.
For example, we have:
8279-2 Circumference.at nipple line:Len:Pt:Chest:Qn
and
8293-3 Circumferenceînspiration:Len:Pt:Chest:Qn
which provide more specificity and permit the key components of the measure to be expressed as one
variable as is the convention in many clinical systems. We call these pre-coordinated codes “molecular”
variables.
Within the LOINC database molecular variables will vary with respect to how many atomic components
are aggregated. As is true in some laboratory areas, methods often are not included as part of a name, nor
are they always reported. The most common molecular aggregation is between functional measure and a
particular site of measurement. (e.g., the many different intravascular sites for blood pressure
measurements.) But in some cases the molecular variables represent combinations of specific measures
and particular methods (e.g., the cardiac output measures). Please note that most molecular variables
could also be accompanied by one or more atomic measures to provide special information about the
measure, e.g., special circumstances of the measure, or the vendor model number or institutional
inventory number of the measuring instrument.
When we have a variable that really reports what would have been contained in the name in a fully
pre-coordinated term, we will place an asterisk in the part that will be reported as a value. For example, a
variable that is used to report the anatomic site as an atomic variable, would have an asterisk (*) in the
system part of the name. The variable used to report the method of a particular measure would have an
asterisk (*) in the method part of the name.
4.3 Radiology Reports
The creation of LOINC codes for naming radiology reports began with a special subgroup of committee
members and a collection of report names from a variety of clinical sites. Radiology LOINC codes were
first released in 2000. A bolus of over 2,000 new codes was added in December 2004, and the Radiology
section of LOINC continues to be an active area of growth.
65
LOINC names for radiology reports follow the general pattern of other clinical observations and
measures, with some subtle differences noted below. Parts, 2, 3, and 5 (type of property, timing, and
scale) correspond exactly in meaning to other clinical and laboratory LOINC codes.
4.3.1
In-progress changes coming through our collaboration with the RSNA
Through our collaboration with the Radiological Society of North America (RSNA), we are jointly
reviewing and unifying our models for naming radiology study terms. Beginning with the June 2015
release and in subsequent releases, LOINC users can expect some significant changes to the naming
conventions used. We began our work with computed tomography terms, and are in the process of
extending the model to other modalities over time.
The collaboration effort has produced a unified model for naming radiology procedures. That new model
is included in this document as Annex - RadLex-LOINC Radiology Playbook User Guide.
For example, one of the new features of the unified model is an attribute that allows for both the region
imaged and a specific structure that is the focus of imaging, e.g., a CT of abdomen with special attention
to the pancreas. The syntax used to describe the Anatomic Location attribute is as follows:
[<body region imaged>] {“+” <body region imaged>} [“>” <imaging focus>]
If there is a single anatomic context associated with a code, it should be specified as <body region
imaged>. The <imaging focus> is an optional element that can identify a more specific anatomic context.
We have now migrated the representation of existing LOINC CT, MR, US, NM and PT terms into this
pattern.
By the time the unification effort is complete, we expect to update most of the contents of this whole
Radiology section with that new guide that describes the unified model in detail. Until then, some
domains of content may be in transition between the old models and the new one. For this reason, we
have left contents of the prior Radiology naming conventions here.
In addition, our detailed review of the radiology terms in both RadLex and LOINC has detected several
terms that are ambiguous, erroneous, or of questionable utility. Following our usual editorial policies,
these terms will be discouraged or deprecated as appropriate. We anticipate that additional curation will
follow as we progress our modeling efforts to the other modalities.
4.3.2
4.3.2.1
Diagnostic Radiology Reports
Component
Like other clinical LOINC codes, the component identifies a particular projection of a three dimensional
space. The component should remove all ambiguity about what projection is being measured.
a) Component/Analyte name
The first subpart of the component field delineates the projections and spatial conditions that are present
during image acquisition. The first subpart is named using the syntax:
66
<descriptor> [<number of views>] [<projection beam orientation>] [<body position>]
The <descriptor> identifies the type of images in the report. For diagnostic x-ray and mammography
studies, the <descriptor> is either View or Views. For diagnostic ultrasound, MRI, CT, and tomography
studies, the <descriptor> is Multisection. The descriptor is the only required field in the component.
Where it is appropriate, additional words are added to the first subpart of the component to clarify the
focus of the exam (e.g., Multisection limited, or Multisection for pyloric stenosis).
The <number of views> is an optional parameter to describe a specific integer number of views in the
projection. Many radiology report names do not specify the actual projections taken, but rather only the
number of views. Some report names describe the number of views in relative terms like “minimum of 3
views” or “less than 4 views”. Where necessary to specify these relative qualifications, we use the
following expressions:
* Gt = greater than
* Ge = greater than or equal to
* Lt = less than
* Le = less than or equal to
The <projection beam orientation> is an optional parameter that specifies the orientation(s) of the beam
with respect to the patient. Widely used abbreviations with unambiguous meanings are employed where
appropriate (e.g., PA, AP, etc.). Multiple images with different orientations are combined using “&”.
The <body position> is an optional parameter to remove ambiguity about the subject’s body position with
respect to gravity. Examples positions include prone, upright, supine, for example:
View PA prone:Find:Pt:Abdomen:Doc:XR
In order to accommodate special groupings of views and challenges, where necessary, we will make an
exception to the principle of not using parentheses in the component for radiology studies (see section
2.1.3). For example:
Views (AP^standing) & (lateral^W hyperextension):Find:Pt:Knee:Doc:XR
b) Report names for portable studies
In general, we do not make names for reports of portable studies, except when the image produced by a
portable study is different than the normal study. For example, portable chest x-ray studies are typically
taken at a shorter distance than those taken in the radiology department, and thus we create separate
LOINC codes for them:
Views AP portable:Find:Pt:Chest:Doc:XR
c) Eponyms and colloquial expressions
Radiology tests are often commonly referred to by eponyms or colloquial expressions. When they are
widely used and understood, these names can represent a concise way to communicate the test(s) being
reported. In many cases, these expressions convey meaning that spans multiple parameters or even
multiple LOINC axes (e.g., COMPONENT, METHOD, and SYSTEM). LOINC names typically employ
these expressions only when their meaning is unambiguous, and confine the use of these expressions
within one axis. For example:
67
View Merchants:Find:Pt:Knee:Doc:XR
d) Challenge tests
The second subpart of the component is chemical, physical, and/or functional challenges. The naming
convention for chemical challenges (e.g., administration of contrast agents) follows the previously
described pattern, including abbreviations for route of administration. For example:
Multisection^ WO & W contrast IV:Find:Pt:Kidney.bilateral+Collecting system:Doc:XR.tomo
When describing administration of contrast into specific spaces for which abbreviations do not exist, the
space is spelled out in full, and preceded by “intra” or “via” according to these guidelines:
We use “intra” when the contrast injected goes directly into this anatomic space, and this space is what is
visualized in the study. For example:
Views^W contrast intra lymphatic:Find:Pt:Lymphatics:Doc:XR.fluor
We use “via” when the contrast injected goes through this device (e.g., catheter) and into the anatomic
space being visualized. For example:
Views^W contrast via T-tube:Find:Pt:Biliary ducts+Gallbladder:Doc:XR.fluor
Views^W contrast via colostomy:Find:Pt:Colon: Doc:XR.fluor
Physical challenges that are present during imaging are denoted using a similar pattern:
[<existence>] <challenge>
where existence is denoted W, WO, or WO & W. The existence of WO & W denotes separate views,
without and with the challenge. For example:
Views^WO & W weight:Find:Pt:Acromioclavicular joint:Doc:XR
4.3.2.1.1 Ambiguity related to “decubitus” in radiology projections and positions
This section describes several issues surrounding radiology naming conventions involving the term
“decubitus” in abdomen and chest x-ray terms, and to describe an LOINC’s accepted naming
conventions. The primary point of confusion concerns an ambiguous naming convention that mixes
projection and body position.
4.3.2.1.1.1
Accepted Term Definitions
Excerpts from Merrill’s Atlas of Radiographic Positions and Radiologic Procedures29:
a) Decubitus
Indicates that the patient is lying down and that the central ray is horizontal and parallel with the floor.
29
Ballinger PW, Frank ED. 10th ed. Vol. 3 Merrill’s atlas of radiographic positions and radiographic procedures. St. Louis:Elsevier
Mosby; 2003.
68
Three decubitus positions are named according to the body surface on which the patient is lying:
(i) Lateral decubitus (left or right)
In a lateral decubitus position, the patient is side-lying. The position is named left or right by the side of
the patient lying on the table.
If the patient’s back is closest to the IR (image receptor, e.g., unexposed x-ray film), this resulting
projection is AP. If the patient’s ventral surface (stomach) is closest to the IR, the resulting projection is
PA.
The AP projection in the left lateral decubitus position is the most common (and perhaps implied)
decubitus view.
However, it is also possible to do a lateral projection in a right or left lateral decubitus (recumbent)
position. (Figure 16-17, Merrill, Vol. 3)
The lateral decubitus position is most often used to demonstrate the presence of air-fluid levels or free air
in the chest or abdomen because air rises to the right side and views, are not obliterated by air that may be
in the stomach.
ii) Dorsal decubitus
In a dorsal decubitus position, the patient is supine. The central ray provides a lateral projection. The
position can be named left or right by the side of the patient that is closest to the IR.
This is also called a cross-table lateral view (abdomen).
This type of position is commonly used in lateral x rays of the spine when the patient cannot be moved
into a standard lateral position and premature infants that cannot be positioned easily.
iii) Ventral decubitus
In a ventral decubitus position, the patient is prone; rarely performed, usually in cases of trauma when the
patient cannot be moved. The central ray provides a lateral projection. The position can be named left or
right by the side of the patient that is closest to the IR.
b) KUB
The Kidneys, Ureters, Bladder (KUB) imaging technique is an Abdomen AP projection, often with the
patient in the supine position. The KUB view includes anatomical structures from the diaphragm to the
symphysis pubis.
4.3.2.1.1.2
Radiology Naming Conventions
In Radiology, LOINC has typically allowed several levels of granularity to accommodate differences in
naming conventions (e.g., specifying laterality or not, explicitly specifying contrast use or not). Different
levels of granularity have been observed in this domain as well.
69
Example local term names:
•
•
•
•
•
•
Abd R Lat Decub XR
Abd R Decub Port XR
Abdomen Decubitus
Chest Decub XR
Chest L Decub XR
Xray Chest Decubitus
4.3.2.1.1.2.1
Decubitus is a body position, not a projection. To add clarity to the names, we will use
decubitus only to refer to the lateral decubitus position.
a) When using decubitus to specify body position, we will explicitly say “L-lateral-decubitus” or “Rlateral-decubitus”. Including the word “lateral” adds clarity as to which projection we are talking
about, and the dashes “-” help link the words together.
(i) Where the intent is to not name a side, we will use “lateral-decubitus”, rather than the more
ambiguous, naked “decubitus”.
4.3.2.1.1.2.2
We will not use the term “dorsal decubitus” to refer to the supine position. Supine will be
used as a valid body position where needed.
a) Because it is common and clear, we use “lateral crosstable” to mean a lateral projection (right or left) in
the supine position, thus encompassing both a projection and body position.
4.3.2.1.1.2.3
The term “ventral decubitus” will not be used to refer to the prone position. Instead, we use
prone as a valid body position where needed.
4.3.2.1.1.2.4
Historically, we created some terms in which there was an implied projection (e.g., AP).
Through careful review, we revised or deprecated these ambiguous terms so as to make the
particular projection explicit include in the name.
a) When a particular projection is not named, it is implied that any potential projection could be
done/reported with this code (e.g., AP, PA, or lateral).
b) An AP L-lateral-decubitus and AP R-lateral-decubitus are considered distinct “views” in our naming
conventions. Thus, use plural “views” and not the singular “view” in such terms.
c) A naked “lateral” in the component means a lateral projection (in any body position).
d) Historically, LOINC included some terms with the abbreviation KUB as a named view. Through
careful review, we have discontinued its use in favor of simply using the projection (AP) and a
specified patient position (e.g., supine or upright) where necessary. This avoids the ambiguity about
what KUB means with respect to the patient position.
e) As in other areas tricky spots of Radiology names, parentheses will clarify which projections are
70
being done in which body positions.
4.3.2.2
Timing
Most radiology reports will have a time aspect of “point in time” (PT). A few reports indicate a specific
time window (e.g., timed fluoroscopy imaging), and these are named in the usual manner, e.g., <numeric
value><S|M|H|W>. Where qualifiers are needed to indicate a relative time frame, we use the following
conventions:
•
•
•
•
Gt = greater than
Ge = greater than or equal to
Lt = less than
Le = less than or equal to
For example, Le 1H
4.3.2.3
System
For all clinical LOINC terms, the system is spelled out in full and should not be ambiguous. For most
radiology reports, the system describes what is being viewed, not only the anatomic area of interest. For
example, a common study to identify anterior glenoid pathology is the West Point view x-ray. Because
this view demonstrates the entire shoulder, not just the glenoid rim, the system is Shoulder:
View West Point:Find:Pt:Shoulder:Doc:XR
We name systems that encompass multiple organ systems by joining them with a “plus” (+). The
individual parameters are arranged in cephalocaudal and/or proximodistal order:
Views:Find:Pt:Spine.cervical+Spine.thoracic+Spine.lumbar:Doc:XR
Views:Find:Pt:Spine.lumbar+Sacrum+Coccyx:Doc:XR
While the system describes what is being viewed, it is not an exhaustive list of all structures in the view.
For example, in practice, a standard lateral view x-ray of the radius and ulna shows these bones in their
entirety as well as the proximal row of carpal bones and the elbow joint. Yet, the system for this report
would simply be Radius+Ulna.
4.3.2.3.1 Vessels
For reports of vascular studies, if the system contains multiple vessels, each vessel is named separately
and connected by a plus (+), (e.g., Celiac artery+Superior mesenteric artery+Inferior mesenteric artery). If
the vessel(s) being viewed is part of a common root, it is named with the common part first, then a dot (.)
separator, and then the division (e.g., Vena cava.inferior). If the vessel(s) are independent branches, then
they are named independently and connected by a plus (+), (e.g., Superior mesenteric artery+Inferior
mesenteric artery).
For studies that view all the vessels in an area, the SYSTEM is typically named in plural form (e.g.,
Lower extremity vessels, Lower extremity veins). The rationale for this is that most angiography studies
demonstrate some vessel branches, not just a single vessel.
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4.3.2.3.2 Brain, head, cerebral, and skull
There is presently much variation in radiology system naming patterns pertaining to the anatomical area
of the head. We have modeled our naming patterns largely after prevailing conventions. We generally use
a system containing Head for reports of MRA, CTA, CT, and US studies. We use the system of Brain
with reports of MRI and nuclear medicine studies, and Skull with plain film study reports. For
conventional fluoroscopic angiography reports, we use a system containing Cerebral when not specifying
a particular artery.
4.3.2.3.3 Extremities
Test names for studies of the extremities often vary in their terminology. The term “arm” technically
means the part of the upper limb from shoulder to elbow, but is also commonly used to refer to the entire
upper limb, and the term “leg” technically means the part of the lower limb between the knee and ankle,
but is also commonly used to refer to the entire lower limb (Dorland’s Illustrated Medical Dictionary30).
In lieu of this, we have included “arm” and “leg” as broad synonyms, but do not use them as a system.
We use “Upper extremity” and “Lower extremity” to refer to the limbs in their entirety or when the
visualized region of the limb is not specified, and we use “Upper arm”, “Forearm”, “Thigh” and “Lower
leg” to refer to segments of the upper and lower extremities. For more specific regions, we name the
system based on the anatomy visualized with that particular method. For example, we name an x-ray of
the upper arm as:
Views:Find:Pt:Humerus:Doc:XR
4.3.2.3.4 Laterality
For most bilaterally symmetric entities, we create separate LOINC codes for radiology reports
differentiated by laterality. Thus, for many studies we have LOINC codes that differ only by the laterality
of the system (e.g., Shoulder, Shoulder.left, Shoulder.right, Shoulder.unilateral, and Shoulder.bilateral).
4.3.2.3.5 Series projections with multiple systems
For radiology reports on a series of projections that include multiple systems (e.g., Ribs+Chest), the order
the projections are listed in the COMPONENT corresponds with the order of the anatomical sites in the
system. In addition, the secondary anatomical site is added to the COMPONENT to clarify which views
were for which anatomical region. For example:
Views lateral & PA chest:Find:Pt:Ribs+Chest:Doc:XR
4.3.2.3.6 Use of dot (.) in system
Using a dot (.) in the SYSTEM signifies that the modifier is a subdivision or component of the main
word. No dot (.) is used when the modifier is just an adjective used for clarification. So, we have:
30
Dorland’s Illustrated Medical Dictionary. 30th ed. Philadelphia: Saunders/Elsevier; 2003.
72
Chest.pleura, but Superficial tissue.
4.3.2.3.7 Method
In general, the method for radiology reports corresponds to the method for other LOINC terms. The
pattern for naming a radiology method is:
<modality>.[submodality]
4.3.2.3.7.1
Method for angiography terms
LOINC terms use the methods of XR.fluor.angio, MRI.angio, and CT.angio to describe angiography
study reports. Radiology systems often use the abbreviations MRA, MRV, CTA, and CTV in test names
of angiography studies. Because MRA and CTA can refer to studies of arteries, veins, or both, they are
equivalent synonyms to the LOINC methods MRI.angio and CT.angio and are included in the database as
synonyms. MRV and CTV are added as synonyms only to terms where the method is MRI.angio or
CT.angio and the system contains the word “Vein” or “Veins.” Note, for angiography studies performed
by Cardiologists, we use the method “Angiography.”
4.3.3
Interventional Radiology Reports
4.3.3.1
Component
Radiology reports for interventional studies under imaging guidance typically contain a component of the
form: Guidance for <indication>, where <indication> is description of the nature of the guidance. For
example:
Guidance for biopsy:Find:Pt:Breast:Doc:Mam
Guidance for drainage:Find:Pt:Kidney:Doc:US
4.3.3.2
System
The system for interventional radiology reports is named for the anatomical structures being viewed,
similar to the pattern for systems of diagnostic radiology reports.
4.3.3.3
Method
In general, the method for interventional radiology reports corresponds to the method for diagnostic
radiology and other LOINC terms. The pattern for naming the method is:
<modality>.[submodality]
5
Tumor registry
In collaboration with North American Association of Central Cancer Registries, Inc (NAACCR, Inc), we
have developed a set of LOINC codes that can be used to communicate tumor registry variables from
clinical institutions to tumor registries and among tumor registries. These LOINC terms map to the
content of NAACCR data set, and include variables for such things as the hospital at which the tumor was
73
first diagnosed, the primary anatomic site of the tumor, it size, its degree of spread at the time of
diagnoses, and a host of other variables of interest to the tumor registries. The NAACCR data set and
other cancer-related demographics are identified by the class TUMRRGT.
The NAACCR standards and an implementation guide for transmitting these LOINC tumor registry
variables within HL7 messages are available from the NAACCR website (http://naaccr.org).
6
Claims attachments
For more information see HIPAA Attachments display in RELMA, the HIPAA Attachment section in
RELMA Users’ Manual, the respective documents published by HL7 Attachments Working Group, and
the Attachments section of the LOINC website (http://loinc.org/attachments).
7
LOINC Document Ontology
This section describes our approach to creating a set of document type codes. This work began as a
collaboration between the LOINC committee and the HL7 document ontology task force, with initial
contributions from Stan Huff, Pavla Frazier, Bob Dolin, Clem McDonald. The background and initial
development of the ontology was described by Frazier et al.31 Over time, we have continued to make
many refinements to this ontology. In particular, we have received exceptional contributions from
colleagues at Columbia University and the U.S. Department of Veterans Affairs.
7.1 Introduction to the use of LOINC document type codes
In creating and maintaining document type codes, it is important to distinguish between the purpose of
local document names and the names represented by the document type code. Document type codes are
created to provide consistent semantics for the names of documents when they are shared or exchanged
between independent facilities or enterprises. The names and codes that are used locally within an
enterprise are entirely under the control of the local enterprise, and these names are valuable to the
workflow and access of information within the enterprise. It is assumed that the exact local name for the
document will be retained in the system that created the document, and that the local name can be sent
along with the document type code when the document is sent to an external organization. The document
type code should only express the meaning in a document name that can be shared between independent
organizations.
For example, it is appropriate to have local document names like “Dr. Smith’s Tuesday Pain Clinic Note”
or “Albuquerque VA General Medicine Consult Note” for use within an enterprise. However, some parts
of these very specific local names are not meaningful outside of the originating enterprise Thus, proper
document type codes would have names like “Outpatient Pain Clinic Note,” or “General Internal
Medicine Consult Note.”
Table 22: Example Clinical Notes
Possible local terms
Document type codes
Dr. Smith’s Tuesday Pain Clinic Note
Outpatient Pain Clinic Note
31
Frazier P, Rossi-Mori A, Dolin RH, Alschuler L, Huff SM. The creation of an ontology of clinical document names. Stud Health
Technol Inform. 2001;84(Pt1):94-8. PubMed PMID: 11604713.
74
Albuquerque VA General Medicine Consult Note
General Internal Medicine Consult Note
The naming rules in this Document Ontology apply primarily to “clinical notes.” For purpose of this
Users’ Guide, a clinical note is a clinical document (as defined by the HL7 CDA Standard), where clinical
professionals and trainees produced the document either spontaneously (e.g., I write my admitting note)
or in response to a request for consultation. “Clinical Notes” provides a better description of the process.
“Clinical Notes” are to be distinguished from patient reports such as radiology reports, pathology reports,
laboratory reports, cardiac catheterization reports, etc., that are generated in response to an order for a
specific procedure. Names for most of these later concepts are accommodated well by the clinical LOINC
naming structure, and many such codes already exist within the LOINC database.
We must also emphasize that the names constructed in LOINC are based on the expected information
content of the document, rather than the document format. This is to say that the same LOINC code
would be used to represent a given document type regardless of whether it was in PDF, text document,
JPG, XML, or HTML formats – if the information content contained by those documents were the same.
7.2 Relationship to other standards
HL7
HL7 will use LOINC codes for clinical document codes, and will not develop an independent document
code system for clinical documents. At its option, HL7 may choose to limit its domain to a subset of
LOINC codes.
The HL7 document type code domain will overlap with similar concepts found in HL7 V2.x (user defined
table 0270 Document Types; user defined table 0496 Consent Types). Our approach to manage this
overlap is:
•
•
Create a mapping from LOINC codes to HL7 V2.x document codes.
Continue to develop LOINC codes to meet the needs of the HL7 V3 domain that are not present
in the V2.x tables.
Relationship to a reference terminology
As soon as possible, the component terms used in the creation of the names of document type codes will
be mapped to either the UMLS Metathesaurus or SNOMED CT. This mapping will help to establish the
meaning of the terms and will allow aggregation and classification of document type codes based on
definitions, computable relationships, and subsumption hierarchies that exist in the reference terminology.
7.3 Elements of Document Type codes
In the following, synonymy or equivalent terms are designated by parenthesis. Document codes are
defined by their component parts. The first list of axis values was published in 2003, and served as the
basis for an initial set of LOINC codes.
Through both empiric analysis and expert review, we have continued evaluating and refining this list. The
following listing contains the current set of axis values for the elements of document type codes that have
been vetted by the LOINC Committee. We are in the process of carefully harmonizing our existing
Document terms with these new values.
75
Kind of Document
Description: Characterizes the general structure of the document at a macro level. Document types are
differentiated based on the need to define distinct document headers.
Allowed Values:
Part Number
Part Name
LP173387-4
LP173388-2
LP173389-0
LP173390-8
LP173391-6
LP173392-4
LP173393-2
LP173394-0
LP173395-7
LP173396-5
LP173397-3
LP173398-1
LP173399-9
LP173400-5
LP173401-3
LP173402-1
LP173403-9
LP193873-9
LP173404-7
LP173405-4
LP173406-2
LP173407-0
LP200113-1
LP173408-8
LP181089-6
LP181085-4
LP173409-6
LP173410-4
LP173411-2
LP173412-0
LP173413-8
LP173414-6
LP173415-3
LP181112-6
LP181116-7
LP181119-1
LP173754-5
LP173755-2
LP173756-0
LP173757-8
LP173758-6
LP173759-4
LP173765-1
LP173766-9
LP173760-2
LP173761-0
LP173762-8
LP173763-6
LP173764-4
LP173118-3
LP173417-9
LP200113-1
LP204161-6
LP181534-1
LP173418-7
LP173419-5
LP173420-3
Administrative note
Against medical advice note
Agreement
Certificate
Birth certificate
Death certificate
Evaluation of mental and physical incapacity certificate
Consent
Abortion consent
Anesthesia consent
Hysterectomy consent
Organ donation consent
Procedure consent
Release of information consent
Sterilization consent
Surgical operation consent
Contract
Driver license
Health insurance card
Health insurance-related form
Health record cover sheet
Legal document
Legal letter
Power of attorney
Request
Prescription request
Advance directives
Do not resuscitate
Rescinded do not resuscitate
Living will
Rescinded advance directive
Diagram
Flowsheet
Form
Instructions
Action plan
ADHD action plan
Anaphylaxis action plan
Asthma action plan
Autism action plan
Complex medical conditions action plan
Cystic fibrosis action plan
Diabetes type I action plan
Diabetes type II action plan
Heart disease action plan
Inflammatory bowel disease action plan
Multiple sclerosis action plan
Muscular dystrophy action plan
Seizure disorder action plan
Discharge instructions
Letter
Legal letter
List
Prescription list
Note
Adverse event note
Alert
76
LP181207-4
LP181204-1
LP181529-1
LP181530-9
LP181190-2
LP181531-7
LP181532-5
LP181533-3
LP181534-1
LP156982-3
LP173421-1
LP183503-4
LP183502-6
Order
Prescription
Prescription for diagnostic or specialist care
Prescription for durable medical equipment attachment
Prescription for eyewear
Prescription for medical equipment or product
Prescription for medication
Prescription for rehabilitation
Prescription list
Photographic image
Report
Case report
Registry report
Further explanation of LOINC’s use of “Note” (i.e. a Clinical Note, also known as “Clinical Document”):
Documents generated by clinicians as part of patient care, which includes notes written at the initiative of
“individual clinic and consulting clinicians.” It does not include clinical reports such as, radiology,
pathology, and cardiac catheter reports that are usually stimulated by a particular order. Clinical
documents meet five criteria, as defined in CDA 1.0: wholeness, stewardship, authentication, persistence,
and human readability.
Type of Service
Description: Characterizes the kind of service or activity provided to/for the patient (or other subject of
the service) as described in the note. Common subclasses of service would be evaluations, consultations,
and summaries. The notion of time sequence, e.g., at the beginning (admission) at the end (discharge) is
subsumed in this axis.
Allowed Values:
Part Number
Part Name
LP173107-6
LP173099-5
LP173109-2
LP173110-0
LP173111-8
LP173100-1
LP173113-4
LP173112-6
LP173114-2
LP173115-9
LP173116-7
LP173117-5
LP173120-9
LP173121-7
LP173122-5
LP173129-0
LP173130-8
LP173131-6
LP173132-4
LP173133-2
LP173134-0
LP173135-7
LP173136-5
LP173137-3
LP173138-1
LP173139-9
LP173140-7
LP173105-0
LP173141-5
LP173142-3
LP173143-1
LP173144-9
LP173145-6
Communication
Conference
Case conference
Consultation
Confirmatory consultation
Counseling
Group counseling
Individual counseling
Daily or end of shift signout
Diagnostic study
Inhalation challenge test
Education
Discharge teaching
Preoperative teaching
Evaluation and management
Care
Crisis intervention (psychosocial crisis intervention)
Disease staging
Disability examination
Social security administration compensation examination
Compensation and pension examination
VA C&P exam.acromegaly
VA C&P exam.aid and attendance &or housebound
VA C&P exam.arrhythmias
VA C&P exam.miscellaneous arteries &or veins
VA C&P exam.audio
VA C&P exam.bones
VA C&P exam.bones fractures &or bone disease
VA C&P exam.brain &or spinal cord
VA C&P exam.chronic fatigue syndrome
VA C&P exam.cold injury protocol
VA C&P exam.cranial nerves
VA C&P exam.Cushings syndrome
77
LP173146-4
LP173147-2
LP173148-0
LP173149-8
LP173150-6
LP173151-4
LP173152-2
LP173153-0
LP173168-8
LP173154-8
LP173155-5
LP173156-3
LP173157-1
LP173158-9
LP173159-7
LP173160-5
LP173161-3
LP173162-1
LP173163-9
LP173164-7
LP173165-4
LP173166-2
LP173167-0
LP173169-6
LP173170-4
LP173171-2
LP173172-0
LP173173-8
LP173174-6
LP173175-3
LP173176-1
LP173177-9
LP173178-7
LP173179-5
LP173180-3
LP173181-1
LP173182-9
LP173183-7
LP173184-5
LP173185-2
LP173186-0
LP173187-8
LP173188-6
LP173106-8
LP173189-4
LP173190-2
LP173191-0
LP173124-1
LP173123-3
LP173125-8
LP173204-1
LP173205-8
LP173200-9
LP173126-6
LP173127-4
LP173128-2
LP204157-4
LP173192-8
LP173193-6
LP173194-4
LP173195-1
LP173196-9
LP173197-7
LP175731-1
LP208913-6
LP173198-5
LP173199-3
LP173200-9
LP173202-5
LP173201-7
VA C&P exam.dental &or oral
VA C&P exam.diabetes mellitus
VA C&P exam.miscellaneous digestive conditions
VA C&P exam.ear disease
VA C&P exam.mental health eating disorders
VA C&P exam.miscellaneous endocrine diseases
VA C&P exam.epilepsy &or narcolepsy
VA C&P exam.esophagus &or hiatal hernia
VA C&P exam.extremity joints
VA C&P exam.eye
VA C&P exam.feet
VA C&P exam.fibromyalgia
VA C&P exam.general medical
VA C&P exam.genitourinary
VA C&P exam.disability in gulf war veterans
VA C&P exam.gynecological conditions &or disorders of the breast
VA C&P exam.hand &or thumb &or fingers
VA C&P exam.heart
VA C&P exam.hemic disorders
VA C&P exam.HIV-related illness
VA C&P exam.hypertension
VA C&P exam.infectious &or immune &or nutritional disabilities
VA C&P exam.large &or small intestines
VA C&P exam.liver &or gall bladder &or pancreas
VA C&P exam.lymphatic disorders
VA C&P exam.general mental disorders
VA C&P exam.mouth &or lips &or tongue
VA C&P exam.multiple exam
VA C&P exam.muscles
VA C&P exam.miscellaneous neurological disorders
VA C&P exam.nose &or sinus &or larynx &or pharynx
VA C&P exam.peripheral nerves
VA C&P exam.initial evaluation post-traumatic stress disorder
VA C&P exam.review evaluation post-traumatic stress disorder
VA C&P exam.prisoner of war protocol
VA C&P exam.pulmonary tuberculosis &or mycobacterial diseases
VA C&P exam.rectum &or anus
VA C&P exam.residuals of amputations
VA C&P exam.miscellaneous respiratory diseases
VA C&P exam.obstructive &or restrictive &or interstitial respiratory diseases
VA C&P exam.scars
VA C&P exam.sense of smell &or taste
VA C&P exam.skin diseases other than scars
VA C&P exam.social &or industrial survey
VA C&P exam.spine
VA C&P exam.stomach &or duodenum &or peritoneal adhesions
VA C&P exam.thyroid &or parathyroid diseases
Evaluation
Annual evaluation
Functional status assessment
Initial evaluation
Admission evaluation
Admission history and physical
Readiness for military duty assessment
Risk assessment and screening
Fall risk assessment
Safety issue assessment
Evaluation and management of a specific problem
Evaluation and management of anticoagulation
Evaluation and management of hyperlipidemia
Evaluation and management of hypertension
Evaluation and management of overweight and obesity
Evaluation and management of smoking cessation
Evaluation and management of substance abuse
Evaluation and management of workers compensation
History and physical
Annual history and physical
Admission history and physical
Labor and delivery admission history and physical
Comprehensive history and physical
78
LP173203-3
LP204160-8
LP173206-6
LP173209-0
LP173213-2
LP173211-6
LP173214-0
LP173215-7
LP173216-5
LP173103-5
LP173218-1
LP173221-5
LP173223-1
LP173222-3
LP175732-9
LP173225-6
LP173224-9
LP200117-2
LP173226-4
LP189614-3
LP173227-2
LP173228-0
LP173229-8
LP173230-6
LP204160-8
LP173231-4
LP207306-4
LP173232-2
LP203673-1
LP203034-6
LP203035-3
LP204130-1
LP173233-0
LP173234-8
LP173235-5
LP173236-3
LP173237-1
LP173238-9
LP173240-5
LP173104-3
LP173242-1
Targeted history and physical
Medical equipment or product
Plan
Plan of care
Progress
Restraint
Surgical operation
Postoperative evaluation and management
Preoperative evaluation and management
Summary
Antepartum summary
Discharge summary
Labor and delivery summary
Maternal discharge summary
Population summary
Summary of death
Summary of episode
Summary of encounters
Transfer summary
Weight management summary
Transplant candidate evaluation
Transplant donor evaluation
Well child visit
Exercise testing
Medical equipment or product
Medication management
Medication administration
Medication reconciliation
Notification
Admission notification
Discharge notification
Visit notification
Outreach
Procedure
Interventional procedure
Pathology procedure
Autopsy
Referral
Respite
Supervisory
Triage
Setting
Description: Setting is a modest extension of CMS’s coarse definition of settings, which have well
defined meanings. Setting is not equivalent to location, which typically has more locally defined
meanings and is reported in other parts of the message. Setting would be limited to one of the following
categories (with some future extensions possible).
Most clinical report names would include a setting (at least at the top level) to avoid confusion between
important classes of reports. For example, The Admission H&P is usually taken to be the Hospital
Admission H&P, but it could be confused with the nursing home H&P if not distinguished by the setting.
Setting is not a required component of the name.
Allowed Values:
Part Number
Part Name
LP173041-7
LP173042-5
LP173043-3
LP173065-6
LP173045-8
LP173046-6
LP173047-4
LP173048-2
Ambulance
Birthing center
Emergency department
Hospital
Intensive care unit
Long term care facility
Custodial care facility
Nursing facility
79
LP173049-0
LP173050-8
LP173051-6
LP173052-4
LP173053-2
LP173054-0
LP173055-7
LP173056-5
LP220237-4
LP173057-3
LP173058-1
LP173059-9
Skilled nursing facility
Unskilled nursing facility
Outpatient
Ambulatory surgical center
Office
Outpatient hospital
Urgent care center
Patient's home
Pharmacy
Rehabilitation hospital
Telehealth
Telephone encounter
Subject Matter Domain (SMD)
Description: Characterizes the subject matter domain of a note.
Allowed Values:
Part Number
Part Name
LP172911-2
LP172915-3
LP172916-1
LP172925-2
LP172918-7
LP172981-5
LP172919-5
LP172923-7
LP172933-6
LP172934-4
LP172935-1
LP172924-5
LP172936-9
LP172987-2
LP172940-1
LP172957-5
LP172988-0
LP173027-6
LP183499-5
LP173035-9
LP172942-7
LP176905-0
LP172943-5
LP172913-8
LP172947-6
LP173027-6
LP172894-0
LP172944-3
LP172946-8
LP172952-6
LP172913-8
LP172921-1
LP172914-6
LP172927-8
LP172953-4
LP172941-9
LP172938-5
LP173032-6
LP172945-0
LP172950-0
LP172947-6
LP175685-9
LP172951-8
LP183500-0
LP175686-7
LP172962-5
Acupuncture
Aerospace medicine
Allergy and immunology
Clinical and laboratory immunology
Anesthesiology
Pain medicine
Audiology
Chiropractic medicine
Critical care medicine
Dentistry
Dermatology
Clinical and laboratory dermatological immunology
Dermatopathology
Pediatric dermatology
Emergency medicine
Medical toxicology
Pediatric emergency medicine
Sports medicine
Trauma
Undersea and hyperbaric medicine
Ethics
Exercise physiology
Family medicine
Adolescent medicine
Geriatric medicine
Sports medicine
Forensic medicine
Forensic psychiatry
General medicine
Internal medicine
Adolescent medicine
Cardiovascular disease
Advanced heart failure and transplant cardiology
Clinical cardiac electrophysiology
Interventional cardiology
Endocrinology
Diabetology
Thyroidology
Gastroenterology
Hepatology
Geriatric medicine
Hematology
Infectious disease
HIV
Medical oncology
Nephrology
80
LP173015-1
LP173023-5
LP173027-6
LP172956-7
LP172926-0
LP172928-6
LP172929-4
LP172930-2
LP172959-1
LP172958-3
LP173011-0
LP172912-0
LP172922-9
LP172944-3
LP172948-4
LP173013-6
LP173012-8
LP172960-9
LP172963-3
LP172964-1
LP172931-0
LP172965-8
LP172898-1
LP172981-5
LP173038-3
LP172968-2
LP172899-9
LP172971-6
LP202989-2
LP172955-9
LP173020-1
LP172973-2
LP172901-3
LP202989-2
LP175686-7
LP172991-4
LP173016-9
LP207940-0
LP172974-0
LP172975-7
LP172902-1
LP172978-1
LP172977-3
LP173029-2
LP172979-9
LP172980-7
LP172967-4
LP172994-8
LP173007-8
LP172982-3
LP172983-1
LP172984-9
LP208907-8
LP172936-9
LP208906-0
LP172920-3
LP208902-9
LP208903-7
LP173002-9
LP172913-8
LP172922-9
LP172937-7
LP172950-0
LP172957-5
LP172961-7
LP192135-4
LP172985-6
LP172986-4
LP172987-2
LP172989-8
Pulmonary disease
Rheumatology
Sports medicine
Medical genetics
Clinical biochemical genetics
Clinical cytogenetics
Clinical genetics
Clinical molecular genetics
Molecular genetic pathology
Mental health
Psychiatry
Addiction psychiatry
Child and adolescent psychiatry
Forensic psychiatry
Geriatric psychiatry
Psychosomatic medicine
Psychology
Multi-specialty program
Neurological surgery
Neurology
Clinical neurophysiology
Neurology neurodevelopmental disabilities
Neurology w special qualifications in child neuro
Pain medicine
Vascular neurology
Nuclear medicine
Nutrition and dietetics
Obstetrics and gynecology
Gynecologic oncology
Maternal and fetal medicine
Reproductive endocrinology
Occupational therapy
Oncology
Gynecologic oncology
Medical oncology
Pediatric hematology-oncology
Radiation oncology
Surgical oncology
Ophthalmology
Optometry
Oral and maxillofacial surgery
Orthopaedic surgery
Orthopedic sports medicine
Surgery of the hand
Orthotics prosthetics
Otolaryngology
Neurotology
Pediatric otolaryngology
Plastic surgery within the head and neck
Palliative care
Pastoral care
Pathology
Anatomic pathology
Dermatopathology
Clinical pathology
Blood banking and transfusion medicine
Chemical pathology
Medical microbiology – pathology
Pediatrics
Adolescent medicine
Child and adolescent psychiatry
Developmental-behavioral pediatrics
Hepatology
Medical toxicology
Neonatal perinatal medicine
Birth defects
Pediatric cardiology
Pediatric critical care medicine
Pediatric dermatology
Pediatric endocrinology
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LP172988-0
LP172990-6
LP173000-3
LP172991-4
LP172992-2
LP172993-0
LP172994-8
LP172995-5
LP172996-3
LP172997-1
LP172998-9
LP172999-7
LP173027-6
LP173003-7
LP220238-2
LP173004-5
LP172954-2
LP172981-5
LP172997-1
LP173026-8
LP173040-9
LP173005-2
LP173006-0
LP173007-8
LP173029-2
LP173008-6
LP173009-4
LP172957-5
LP172972-4
LP173035-9
LP173010-2
LP173014-4
LP204156-6
LP173018-5
LP172939-3
LP172896-5
LP172969-0
LP172996-3
LP173016-9
LP173017-7
LP173037-5
LP173019-3
LP173021-9
LP173022-7
LP173024-3
LP173025-0
LP173028-4
LP172932-8
LP172999-7
LP173029-2
LP173030-0
LP207940-0
LP173031-8
LP207300-7
LP173033-4
LP183499-5
LP173039-1
LP173034-2
LP173036-7
LP173001-1
LP185997-6
Pediatric emergency medicine
Pediatric gastroenterology
Pediatric transplant hepatology
Pediatric hematology-oncology
Pediatric infectious diseases
Pediatric nephrology
Pediatric otolaryngology
Pediatric pulmonology
Pediatric radiology
Pediatric rehabilitation medicine
Pediatric rheumatology
Pediatric surgery
Sports medicine
Pharmacology
Clinical pharmacology
Physical medicine and rehabilitation
Kinesiotherapy
Pain medicine
Pediatric rehabilitation medicine
Spinal cord injury medicine
Vocational rehabilitation
Physical therapy
Plastic surgery
Plastic surgery within the head and neck
Surgery of the hand
Podiatry
Preventive medicine
Medical toxicology
Occupational medicine
Undersea and hyperbaric medicine
Primary care
Public health
Community health care
Radiology
Diagnostic radiology
Interventional radiology
Nuclear radiology
Pediatric radiology
Radiation oncology
Radiological physics
Vascular and interventional radiology
Recreational therapy
Research
Respiratory therapy
Social work
Speech-language pathology
Surgery
Colon and rectal surgery
Pediatric surgery
Surgery of the hand
Surgical critical care
Surgical oncology
Thoracic and cardiac surgery
Cardiac surgery
Transplant surgery
Trauma
Vascular surgery
Tumor board
Urology
Pediatric urology
Wound care management
Role
Description: Characterizes the training or professional level of the author or the party responsible for the
content in the document. The role category is a high-level classification that does not get as detailed as
specialty or subspecialty so as to avoid potential overlap with the subject matter domain axis.
82
Allowed Values:
Part Number
Part Name
LP173066-4
LP173067-2
LP173068-0
LP173069-8
LP173071-4
LP173072-2
LP173073-0
LP203036-1
LP173074-8
LP173075-5
LP173076-3
LP173077-1
LP173078-9
LP173079-7
LP173080-5
LP173081-3
LP173082-1
LP173083-9
LP181523-4
LP173084-7
LP173090-4
LP173085-4
LP173086-2
LP173087-0
LP173088-8
LP173089-6
LP173091-2
LP173092-0
LP173093-8
LP173094-6
LP173095-3
Assistant
Case manager
Clerk
Counselor
Hygienist
Interdisciplinary
Team
Rapid response team
Medical assistant
Nurse
CRNA
Certified nursing assistant
Clinical nurse specialist
Nurse midwife
Nurse practitioner
Licensed practical nurse
Registered nurse
Patient
Pharmacist
Physician
Physician assistant
Physician attending
Physician consulting
Physician fellow
Physician intern
Physician resident
Student
Medical student
Nursing student
Technician
Therapist
* Physician subsumes medical physicians and osteopathic physicians.
7.4 Rules for Creating Clinical Notes from Multiple Components
Names for required clinical notes would be constructed by picking entries from the Kind of Document
axis and at least one of the other four axes (see exceptions below). The LOINC committee will create
LOINC codes for all required combinations (not all possible combinations).
The original document ontology terms were created only for the document type of “note” and with the
general naming pattern:
<Subject Matter Domain> : <Training / Professional Level>: <Setting>: <Type> : Note
As we have revised and refined the elemental axes in the document ontology, simple names would be
constructed and ordered as follows:
Table 23. Document Ontology LOINC Naming Rules
Component
Property
Time
System
Scale
Method
Class
<Type of Service> <Kind of Document>
Find
Pt
<Setting>
Doc
<SMD>.<Role>
DOC.ONTOLOGY
83
In general, combinations from within an axis are allowed in a term name where they make sense
(typically SMD and Service), but are disallowed where they do not (typically Role and Setting).
Combinations will be represented with a plus (+), so as to distinguish from elements containing “and” or
“&”. Where a particular element is not defined for a given term and leaves a LOINC axis blank, the
LOINC name will include the {} naming convention. For example, if a Setting is not designated, the
System will be “{Setting}”. Where neither the SMD nor Role is specified, {Role} is used in the Method
(as of LOINC version 2.54).
LOINC codes for clinical notes designed according to this model and are assigned a class of
DOC.ONTOLOGY. The class name was changed in LOINC version 2.50 from DOC.CLINRPT to
DOC.ONTOLOGY, a more representative name for all types of documents (not just clinical reports)
included in the LOINC Document Ontology.
Example LOINC codes in the Document Ontology include:
Table 24. Example Document Ontology LOINC Codes
Component
Property
Time
System
Scale
Method
Class
Group counseling note
Find
Pt
Hospital
Doc
{Role}
DOC.ONTOLOGY
Note
Find
Pt
Outpatient
Doc
{Role}
DOC.ONTOLOGY
Admission evaluation note
Find
Pt
{Setting}
Doc
General medicine
DOC.ONTOLOGY
History and physical note
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
For every clinical note term we create with a designated Setting, SMD, and/or Role, we will also create a
general “roll-up” term where the Setting, SMD and Role are not specified, i.e. they are defined as
{Setting} and {Role}. The LOINC Committee has agreed not to create a general document code in some
cases, including:
1) The Component contains only one axis value, either a Type of Service or Kind of Document.
Such a generic code (absent the other attributes) would violate the current policy to include the
Kind of Document plus at least one other axis value.
2) The general type of clinical document is not likely to ever exist
Example LOINC codes that do not have a general clinical note term include:
Table 25. LOINC Code Exceptions to Creating a General Clinical Document Code
Component
Property
Time
System
Scale
Method
Class
Anesthesia consent
Find
Pt
{Setting}
Doc
Patient
DOC.ONTOLOGY
Organ donation consent
Find
Pt
{Setting}
Doc
Patient
DOC.ONTOLOGY
Health insurance card
Find
Pt
Doc
Patient
DOC.ONTOLOGY
Triage+Care note
Find
Pt
Doc
Nurse
DOC.ONTOLOGY
Prescription request
Find
Pt
{Setting}
Emergency
department
Pharmacy
Doc
Pharmacist
DOC.ONTOLOGY
7.4.1
Exceptions to Rules for Creating Clinical Notes
As noted above, the current policy for creating clinical notes is to include the Kind of Document plus at
least one other axis value. The LOINC Committee has agreed to make exceptions to the Document
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Ontology rules for cases where only Kind of Document is commonly designated (e.g. Driver license).
Example LOINC codes that are approved exceptions containing only a Kind of Document:
Table 26. LOINC Codes with only a Kind of Document
Component
Property
Time
System
Scale
Method
Class
Administrative note
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Asthma action plan
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Birth certificate
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Death certificate
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Case report
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Driver license
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Photographic image
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
Prescription list
Find
Pt
{Setting}
Doc
{Role}
DOC.ONTOLOGY
The LOINC Committee also recognizes the need for terms with only a general Kind of Document (e.g.
Letter, Note, Report) designated. We have agreed to create such terms, however, they will have a status of
“discouraged” to caution users. If these general terms are used, we strongly recommend that they are
used in a post-coordinated manner in conjunction with one of the LOINC terms included in the LOINC
Document Ontology associated observations panel [LOINC: 80582-0] to carry the relevant attribute
specifications.
7.5 Document Ontology Content in the LOINC Distribution
Beginning with LOINC version 2.44 (June 2013), a delimited text file containing the relationships
between clinical document terms (i.e. those within the class of DOC.ONTOLOGY) and their associated
ontology axis values is available as a separate download from http://loinc.org. The document ontology
axis values have been assigned LOINC Part identifiers and classified according to their document
ontology axis. This file defines the relationships between a given LOINC term and its ontology axis
values through these fields: LoincNumber, PartNumber, PartTypeName, PartSequenceOrder, PartName.
These fields are largely self-explanatory, but of note is that the PartTypeName corresponds to the
document ontology axis, and the PartSequenceOrder is relevant for terms that combine axis values from
within an axis (see section 7.4).
7.6 Future Work
We continue active development and refinement of the Kind of Document axis. As we continue this work,
we intend to develop equally specific definitive documents for other kinds of health care associated
documents.
7.7 Proposing new LOINC document terms
New LOINC document type codes can be proposed using the process described in Appendix D. In
general, new term proposals that contain allowed combinations of existing axis values will be made
expeditiously by Regenstrief staff. Requests for document titles containing new axis values to be added to
the ontology will be reviewed by the LOINC committee, and thus their final modeling may take a bit
longer.
8
Panels (Batteries)
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Beginning with version 1.0o, the LOINC database was expanded to include order sets/panels. We use the
word “panel” to mean collector terms that contain links to an enumerated set of discrete child elements.
Across domains, this generic concept of a collection might be called a battery, form, data set, etc. The
same general panel structure in LOINC is used to represent all of these kinds of collections.
8.1 Goals
Our work in creating panels was stimulated by many requests for a standard set of test order codes from
medical information system vendors who want to install their systems with a usable starter set of standard
codes for common orders. They also want standard codes to ease the cross communications among
merging hospitals.
LOINC codes have been defined for most individual laboratory observations and for many clinical
observations, and claims attachments. The same LOINC codes can be used to order individual laboratory
and clinical observations, as well as to report the result. For example, a LOINC code for Blood
Hemoglobin (LOINC # 718-7) could be used as easily to order the test as to report its result. In HL7
messages, the field where the code is used indicates its role as an order (e.g. OBR-4) or a result
observation (OBX-3).
Similarly, pre-existing LOINC codes could also be used to order more complex observations. The LOINC
code used to order Urinary Creatinine Clearance (LOINC # 2164-2) actually implies an order for two
distinct measures (serum creatinine and 24-hour urine creatinine) that are used to calculate the creatinine
clearance.
However, the existing single value LOINC codes could not be used to order many laboratory and clinical
procedures that are ordered as a single-named test (battery), such as CBC, urine dipsticks, blood
differential count, and LDH isoenzymes. Similarly physicians order blood pressure measures and expect
to get (at least) the diastolic blood pressure and the systolic blood pressure. Though these are separate
observations, for practical purposes one is never measured without the other.
Initially, we created LOINC codes for the common “fixed” packages of observations. By fixed, we mean
that certain kinds of measures will always be part of the battery, and the production of that particular set
of measurements is tightly bound to the procedure, instruments that produce the values, or by a
government mandate (e.g., LOINC # 24325-3: Hepatic function HCFA 2000 panel).
Over time, we have evolved our approach to building panels of other observation collections. (For
information on using the ORDER_OBS field of the LOINC database to help find panels that could be
used as orders, see section 10.3.)
8.2 Types of results found in panels
To understand the rules about how LOINC creates panels and how to map your local panels to LOINC
panels, it is important to distinguish among several kinds of “results”.
8.2.1
Primary measurements or observations
These observations report key measured results, and may indicate the presence/absence or amount of a
substance or organism in the sample. For example, in an electrolytes panel, measured amounts of sodium,
potassium, chloride, and bicarbonate would be the primary measures.
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8.2.2
Derived observations
These observations are derived from mathematical or logical operations on the primary measurements.
For example, in an electrolytes panel, the anion gap is a derived measure that is calculated by subtracting
the concentrations of chloride and bicarbonate (anions) from the concentrations of sodium and potassium
(cations).
8.2.3
Ask at order entry (AOE) questions and other associated observations
These observations are obtained from the requester as part of the test order and are generally delivered
back to the requester as part of the result package. For example, the concentration of inspired oxygen is
always an AOE question for blood gas measurements. Similarly, the date of last menstrual period is an
AOE question for pap smears.
Other kinds of observations are operationally treated in a similar manner although they may not be
“questions” in the literal sense. For example, the volume and times (start, stop, duration) of urine
collection are often sent along with the order and back again with the results. We call these “associated
observations” and consider them like AOEs for the purpose of this discussion.
8.2.4
Impressions, interpretations, and comments
LOINC defines an impression/interpretation as a summary statement about multiple observations. This
kind of summary observation is often included in collections of results sent back to the requester. (Such
summary observation terms in LOINC have the Property of “Imp”, for impression, in their name).
As an aside, we note that decisions about test results being outside of normal range are best reported with
the Interpretation Code (commonly referred to as the “Abnormal flag”) field of the HL7 OBX structure
and not as a separate interpretation observation.
8.3 LOINC rules for panel names
We use most of the same general LOINC naming rules for panels as we do for individual observations.
Here we describe some of the key unique features of panel names.
8.3.1
Component
If a government authority recognizes the panel or order set, we will name such panels with the year that
the recognition took effect. For example, LOINC includes the “Comprehensive metabolic 2000 panel”.
For panels consisting of more than three constituent tests, the component name will be a concatenation of:
(1)
(2)
A name (e.g., Hemogram, Differential count, Vital Signs) to convey the content of the panel
The word “Panel” included to unambiguously identify that this LOINC term refers to a panel or
battery
In the case that a well-defined panel exists but has no conventional name or the panel consists of three or
less constituents, we will include each of the distinct measured entities separated by ampersand (&) in the
Component. We may also use a more efficient syntax that implies a repeat of the first part of the name,
e.g., Chlamydia Ab IgM & IgG Panel.
In general, LOINC creates different codes for panels that contain reflex testing versus those that do not.
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Such panels will include “reflex” in the Component name, and the general approach is to name the base
panel and the kind of test(s) or test panel done as a reflex in the panel name. The reflex test(s) can be a
single test, a group of tests, or a test panel.
8.3.2
Property and Scale
Because the Property typically varies across the elements of a panel, the Property (i.e. the second part of
the LOINC name) for the panel term may be populated by a dash (-). Likewise, the Scale (5th part of the
LOINC name) will be populated by a dash (-) if the panel elements contain different scales.
8.3.3
Time Aspect and System
Because these parts of the LOINC name are typically consistent across the primary measures of a panel,
the Time Aspect and System of a panel name are usually specified with the same conventions that apply
to observation terms.
8.3.4
Examples of LOINC Panel names
The following are a few examples of LOINC Panels (Order Set Names):
Table 27: Examples of LOINC Panel Names (Order Set Names)
LOINC_NUM
24358-4
24359-2
24317-0
LOINC Fully Specified Name
Description
Hemogram WO platelets panel:-:Pt:Bld:Qn
Hemogram WO platelets & W manual differential
panel :-:Pt:Bld:Qn
Hemogram & platelets WO differential panel::Pt:Bld:Qn
HCT & HGB & WBC & RBC & Indices
24338-6
Gas panel:-:Pt:Bld:Qn
24336-0
Gas panel:-:Pt:BldA: Qn
24339-4
Gas panel:-:Pt:BldV:Qn
29274-8
Vital signs measurement:Find:Pt:^Patient^Multi
24357-6
Urinalysis macro (dipstick) panel:-:Pt:Urine:-
29576-6
Bacterial susceptibility panel:-:Pt:Isolate:OrdQn
Hemogram & Differential Count
HCT & HGB & WBC & RBC & Indices & Platelets
pH & PO2 & PCO2 on blood without specifying whether
arterial, venous, or other source. The report would usually
include an observation about the inspired O2 sent along with the
report. It may include a variety of other patient characteristics
sent by the requester and a variety of computed variables.
pH & PO2 & PCO2 on arterial blood. The report would usually
pH & PO2 & PCO2 on venous blood. The report would usually
Diastolic Blood Pressure & Systolic Blood Pressure & Pulse
Rate & Respiratory Rate
Urinalysis dipstick results. Usually includes Glucose, Bilirubin,
estimate of leukocytes, estimate of RBCs, estimate of bacteria,
Ph, Specific gravity. But we do not make distinctions about the
exact set of measures on the dipstick. The ordering clinician will
not necessarily know what particular dipstick is being used and is
not able or interested in making those distinctions.
Would include susceptibility results for the antibiotics relevant to
the isolates and the kind of culture.
8.4 Representing conditionality
Within the LOINC panel structure, we can set an attribute for each element of the panel that denotes
whether or not it should be present (conditionality) in the panel when resulted. The primary measures are
always required, but the other elements of the panel may have different kinds of conditionality.
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The conditionality attribute is visible on the details pages for panel terms under the column “R/O/C” and
stored in the “ObservationRequiredInPanel” field of the LOINC panels and forms file (available for
download from the LOINC website).
Through version 2.48 of the LOINC database, the conditionality choices were limited to R (Required), O
(Optional) and C (Conditional). Examples of simple order sets with terms that are either R or O:
Table 28: Example Order Sets
24358-4
Hemogram WO platelets panel
-
Pt
Bld
Qn
R/O/C
26464-8
Leukocytes
NCnc
Pt
Bld
Qn
R
26453-1
Erythrocytes
NCnc
Pt
Bld
Qn
R
718-7
Hemoglobin
MCnc
Pt
Bld
Qn
R
20570-8
Hematocrit
VFr
Pt
Bld
Qn
R
30428-7
Mean corpuscular volume
28539-5
Erythrocyte mean corpuscular hemoglobin
28540-3
30384-2
30385-9
24326-1
EntVol
Pt
RBC
Qn
R
EntMass
Pt
RBC
Qn
R
Erythrocyte mean hemoglobin concentration
MCnc
Pt
RBC
Qn
R
Erythrocyte distribution width
EntVol
Pt
RBC
Qn
O
Erythrocyte distribution width
Ratio
Pt
RBC
Qn
O
-
Pt
Ser/Plas
Qn
R/O/C
Electrolytes 1998 panel
2951-2
Sodium
SCnc
Pt
Ser/Plas
Qn
R
2823-3
Potassium
SCnc
Pt
Ser/Plas
Qn
R
2075-0
Chloride
SCnc
Pt
Ser/Plas
Qn
R
2028-9
Carbon dioxide
SCnc
Pt
Ser/Plas
Qn
R
330373
Anion gap
SCnc
Pt
Ser/Plas
Qn
O
Starting with version 2.50 (December 2014), we expanded the choices beyond R, O and C to include R-a
(Required with alternative), Rflx (Reflex) and Rflx-a (Reflex with alternative). The expanded choices
better accommodate reflex tests, cases in which more than one test could be used to fulfill a given
requirement of the panel, and focus the use of C (which had previously been used as a “catch-all” for
many types).
Table 29 describes the expanded set of conditionality choices.
Table 29: Options for Term Conditionality within Panels
Code
Meaning
Discussion /Definition
R
R-a
Required
Required
with
alternatives
Means this test must be included.
Means required but has alternatives. The alternatives will usually be paired, and both will be marked with the R-a
code. Results for at least one member of the pair must be included in the panel to satisfy the required condition, but
both may be included. The C, conditional, had been used to deal with these cases in the past.
The rule for pairing up of the alternatives for a given purpose will be described in narrative usually in the panel
description because the same rule will apply to many pairings in the panel. For example, the LA panel includes lots
of coagulation measures and almost all can be reported as an actual time and/or as the ratio of patient time to the
normal time. Measures of the same clotting function that differ only by how they are reported would be considered
paired alternatives in this panel. More specific pairing rules may also be asserted in the “condition for inclusion” field
associated with each item in the panel.
C
Conditional
Means that the required status of a given variable is depends on other factors. This was too much of a waste basket
category, which is why we added some new categories to specify what had usually been lumped as conditional.
O
Optional
Means the variable may be included or not, but whether it is included or not has no bearing on the whether a given set
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of result represents the given panel. Simple calculations derived from other reported measurements and ask at order
entry questions are almost always optional.
Rflx
Reflex
Means this test will be included in the panel only if it satisfies a reflex condition based on other results in the panel.
Such cases had also been lumped under the conditional code in the past. In general, we will not define specific rules
for reflexing except in very general terms.
Rflx-a
Reflex with
alternatives
Means that that the test is a reflex but that another test in the panel can serve as an alternate and either or both of
these reflex tests can be reported. But if the reflex condition is met, at least one of the alternative pairs must be
included. As in the case of R-a, what tests pair up as alternative will be defined in narrative in the panel description of
the condition for inclusion field.
If more than one measure can serve as a primary measurement, then both of them will be required with
alternatives (R-a), and the criteria is that at least one of them must be present. An example would be the
absolute count of neutrophils versus the percentage of total white count of neutrophils in a differential
blood count – if one is absent the other must be present (of course they are both often reported).
The criteria or explanation for when the tests with R-a, Rflx and Rflx-a should be included in the results
for a particular panel can be seen on the comprehensive details page available within RELMA and the
online LOINC search application (search.loinc.org).
Note that the conditionality assigned to a term is panel-specific. In other words, a given test may be
required in one context and optional in another, which is why both the conditionality and criterion for
inclusion only appear in the panel details and not in the individual term details.
We should acknowledge that LOINC includes many panels without the required status having been
marked and that the conditional status has not been employed everywhere that it could have been, and that
many terms marked as conditional under the previous model probably would be better categorized as
required with alternatives, reflex, or reflex with alternative. (We still have LOINC development work to
do.)
8.4.1
Lupus anticoagulant (LA) testing as an example of complex conditionality
Here we describe lupus anticoagulant (LA) testing as a prototype to illustrate the use of conditionality. At
the core of lupus anticoagulant (LA) testing is a three step process using a given coagulation measure,
such as dRVVT. The first is a screening to determine whether a clotting abnormality exists. The second is
a mixing study, in which the patient specimen is mixed with pooled normal plasma (PNP) and the same
test (e.g. dRVVT) is rerun. This second test is used to evaluate whether the clotting problem is due to a
clotting factor deficiency, such as occurs in Hemophilia. The third is yet another repeat of the same test
(e.g. dRVVT) mixed with excess phospholipid – also called the confirmatory test. Lupus anticoagulant is
declared present if the addition of excess phospholipid normalizes the result.
There are a number of variations in LA testing algorithms across laboratories. Some labs do the confirm
test second and the mixing study third (if needed). The International Society of Thrombosis and
Haemostasis (ISTH) recommends using two clotting tests: dRVVT and aPTT-LA (lupus sensitive), each
reflexing to confirm and/or mixing study. However, at least two labs use three screening tests, adding PT
to the dRVVT and aPTT-LA, reflex to mixing and confirm studies from these, and add further reflex
testing, including thrombin time and from that a reflex to reptilase time. There are also variations in how
the results are reported, e.g. as actual clotting times and/or as ratios of the actual time to the time of
normal. And some labs define the kind of phospholipid they use for the confirm study, i.e., hexagonal or
platelet derived phospholipid.
90
The LA panel for three screening tests shown below illustrates a number of issues related to conditionality
described above. The three screening tests (dRVVT, aPTT and PT) are all required but can either be
reported as the actual result or actual/normal, therefore all six terms are assigned the conditionality R-a.
The mixing and confirmatory tests as well as thrombin time and reptilase time are only run if any of the
screening tests are out of range and when run, can also be report as actual or actual/normal; therefore, all
of these terms are assigned Rflx-a. The dRVVT and aPTT percent correction and screen to confirm ratio
may not be reported by all laboratories and therefore have an O status. Finally, the overall interpretation
must be reported and so is assigned R.
Figure 1. Details page for three screening test lupus anticoagulant panel
8.5 Approach to creating and defining distinct panels in LOINC
8.5.1
General approach
The defining characteristics of a LOINC panel term include the enumerated set of child elements and the
conditionality of those elements. Thus, users must pay close attention to the full panel structure in order to
know whether it is an appropriate representation of their local panel.
When LOINC defines a panel, it will include all of its primary measurements/observations (flagged as
required), and will also include commonly reported derived observations (flagged as optional). When
laboratories report an interpretation across many observations in a panel, such as the differential count or
a serum electrophoresis, the LOINC panel will include an interpretation term specific to that panel
(flagged as optional). Likewise, the panel will also contain commonly included AOE variables and other
91
associated observations (flagged as optional).
LOINC will not define distinct panels for different collections that vary only on the optional elements
(whether or not there is an interpretation, an additional derived calculation, variables sent along with the
request, etc.). As a corollary, users can match their local panels to LOINC panels whether or not their
reported results include those optional elements.
During the several years prior to the LOINC 2.56 release, the number of requests for panel terms steadily
increased. At the same time, newer laboratory methods have led to the creation of lab kits that could be
customized by the end-user in terms of the individual tests that were run. For example, if a kit includes
ten different assays, one hospital might implement six while another hospital might implement all ten of
the assays. In addition, each version of the kit could potentially have different combinations of tests.
Many of our requests were for panels that differed only slightly from existing panels, likely in part due to
differences in the aforementioned kit implementation. Going forward, it now appears impractical to create
a unique panel for every hospital, laboratory, and test kit. Therefore, at the June 2016 meeting, the
Laboratory LOINC Committee agreed upon the following business rules for new panel requests:
8.5.1.1
Panels for test kits
We will make generic panels for groups of tests that are not specific to a particular manufacturer or test
kit but that are method- and system-specific. Such panels will not have conditionality or cardinality
specified. As test kits evolve over time, additional children may be added, but none will be removed
except in limited circumstances. Examples of such panels are:
79381-0 Gastrointestinal pathogens panel - Stool by Probe and target amplification method
82180-1 Meningitis+Encephalitis pathogens DNA and RNA panel - Cerebral spinal fluid by Target
amplification with non-probe based detection
Panels for individual laboratories and/or hospitals
In general, we will not create new panels for every hospital and laboratory, based on their unique
combination of elements. However, we likely will make panels when many hospitals and/or labs use the
exact same set of elements.
8.5.1.2
Fully specified panels
We will make panels with conditionality and cardinality details in cases where a specific guideline or
standard of care exists, such as the lupus anticoagulant screening panel examples above.
8.5.1.3
8.5.2
Preference for methodless panel definitions
In most cases, LOINC will not make up different panel terms for the same set of tests done by different
methods. Because of the possible mixtures of methods within a panel, representing these distinctions
would cause an explosion of the distinct panel, which would (usually) be a burden on the ordering
provider. Further, in a given setting the ordering provider can only order the methods that are provided by
his usual producer. Implied in the order is “Give me the battery produced by your usual methods”. Thus,
as a general approach we tend to create panels with child elements that are methodless.
In special circumstances though, we do create panels of method-specific observations. For example, we
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have different panels for screen and confirm methods. In such cases, the method specification is defining
characteristic of the panel.
8.5.3
Special cases where enumeration of child elements is not practical
There are special cases where LOINC may define a panel term by a narrative definition because it is not
practical to fully enumerate all of the possible child elements and their conditionality.
For example, public health, veterinary medicine, and other laboratories that are not charging Medicare or
Medicaid for the tests they perform are not bound by the rules that penalize labs for performing and
charging for tests that the practitioner did not explicitly order. This makes creating order panels a little
easier.
In the case of public health, the tests performed by a laboratory in response to a request may be chosen
from a list of many possible tests, based on information provided by the requester, and the laboratory’s
judgment. For example, CDC’s “Campylobacter, Helicobacter and related organisms identification and
subtyping” (CDC-10127) order can include tests that identify the phenotype, the genotype, Penner
serotype, PFGE, or AST, and might use multiple test procedures for each of these.
9
Evolving principles for naming collections
9.1 Goals and general approach
We are in the process of evolving our model for naming collections in LOINC. Our goals in refining this
model are to:
•
•
•
•
Create names that are consistent across different subject domains within LOINC
Make it easy to create a list of all codes that could be used as document type in CDA
Make it easy to create a list of all codes that could be used as section headings in CDA
Avoid proliferating names
To this end, we are developing rules for naming of collections will apply to both laboratory collections
(CBC, CHEM7) coded and structured clinical collections (Vital Signs), documents (Admit History and
Physical Exam), Apgar scores, Braden Scale, Pain scales, etc. There will be two categories of names for
collections:
• Names for panels with enumerated discrete contents, and
• Names for general collections of information.
Using the existing panel mechanisms, the LOINC database will record the association between LOINC
collections and individual observations where these associations are known. For example, LOINC already
records the expected contents for CBC, Liver Enzymes, etc. It will also include definitions for Vital
Signs, Cardiac Catheterization, Braden Scale, surveys, etc. We will create a single LOINC code for any
general collection of information where the information content of the collection is the same, regardless
of whether the content is a text document, a scanned image of text, or a sound file of the same
information.
Since collections are named by their real or anticipated contents, the same LOINC code could be used as
93
either a document type or as a section type.
9.2 Collections as orders and observations
The same LOINC code will be used for ordering a procedure, naming the document produced as the
description of the procedure, or naming the structured and coded set of observations from the procedure.
For panels, the same code for CBC would be used as the ordered item in an order record or message, and
as the panel identifier in the OBR segment of a result record or message. The same pattern would be
followed for laboratory procedures and clinical procedures.
For general collections, the same code would be used as the ordered item in an order record or message,
and as the result identifier in a result message. For example, the general collection name could be used in
a result message as the identifier of a document type, as a section label, as the universal identifier in an
OBR segment, or as the identifier in and OBX segment depending on the circumstances. The same pattern
would be followed for radiology procedures and clinical procedures.
We are not taking away the flexibility of having the ordered code be different from the result code. For
example, it is often desirable for the order code to be less specific and more abstract than the result code.
LOINC would contain codes for something like “Exercise EKG” with the expectation that the result could
come back as “AHA Protocol Stress EKG Result”. The point is that when appropriate we would use the
same LOINC code in the contexts of orders and results. We would NOT make LOINC codes that meant
“CBC Order” and “CBC Result”, we would use the same LOINC code for CBC in both orders and
results.
Current practice would also continue where a “pure” procedure is ordered and discreet results would be
returned. For example, Urine Microscopic Exam could be ordered and discreet values for cell types, casts,
amorphous material, etc. would be returned.
9.3 LOINC SCALE for collections
The SCALE for panels will be a dash (-). The Scale for general information collections will be “Doc”,
short for document, which is used in the most general sense of a text document, image, scanned text
image, etc. “Doc” would replace the current use of Nar (narrative) or Nom (nominal) for general
information collections in the current LOINC database.
The LOINC committee will review current contents of the LOINC database and modify names
appropriately to conform to the new conventions. We will not implement the name changes until after the
current Attachments NPRM is final.
9.4 Examples of proposed changes according to new policy
Table 30: Example of Proposed Changes
LOINC#
Component
Property
Time
System
Scale
Method
Class/Type
24358-4
Hemogram panel
-
Pt
Bld
-
PANEL.HEM/BC
24320-4
Basic Metabolic HCFA 98 panel
-
Pt
Ser/Plas
-
PANEL.CHEM
24362-6
Renal Function HCFA 2000 Panel
-
Pt
Ser/Plas
-
PANEL.CHEM
94
34566-0
Vital signs panel
-
Pt
^Patient
11488-4
Consultation note
Find
Pt
34066-1
Boxed warning section
-
-
Doc
DOC.REF.
35511-5
Background information section
-
-
{Setting}
^FDA package
insert
^Clinical trial
protocol
-
Doc
DOC.REP.CTP
35660-0
Path report.final diagnosis section –
text
Imp
Pt
Specimen
Doc
TUMRRGT
24534-0
Multisection
Find
Pt
Abdominal
vessels
Doc
Doc
PANEL.VITALS
{Role}
US.doppler
ATTACH.CLINRPT
RAD
10 Additional Content in the LOINC Distribution
10.1 LOINC Answers and Answer Lists
Across many domains, the meaning of a particular observation can be best understood in the context of
the set of possible answers (result values). For example, the questions/items in standardized assessment
instruments often have highly specialized, fixed answer lists. In many contexts, it is the answer list that
most completely defines the meaning of concept represented by the question. Additionally, because many
of the answer choices are highly specialized, few are represented by existing codes in reference
terminologies. For these reasons, we have created a structured representation of answer lists in LOINC.
We identify the binding of LOINC observation codes to answer lists as “normative”, “preferred”, or
“example”. Normative lists are those specifically defined by a validated instrument or other authoritative
source. When using LOINC codes bound to normative answer lists, only answers in the specified set are
allowed as result values. Examples of sources for Normative answer lists are PROMIS or the Clinical
Pharmacogenetics Implementation Consortium (CPIC). Preferred lists contain a set of answers that users
are strongly encouraged to use. They represent a recommended set, however, in contrast to a Normative
list, alternate result values may be used if necessary. Preferred lists may come from a variety of sources,
including professional organizations (e.g., American Physical Therapy Association), device
manufacturers, and government (e.g., Centers for Diseases Control and Prevention, National Eye
Institute). Example lists are meant to be illustrative of possible result values. Users can also think of them
as a starter set to which they may add or subtract depending on their use case. Many of the Example
answer lists are in the lab domain, where different labs may report similar results in a variety of ways,
such as “Positive”, “Present”, “Detected”, “Abnormal” or “Out of range” but for which we have a single
Example answer list.
Not all answer lists are fully enumerated within LOINC. For example, some questions may have their
answers drawn from a large terminology such as ICD-9-CM or CPT and we do not reproduce those lists
within the LOINC structure. Answer lists that are not fully enumerated within LOINC are flagged to
indicate that they are externally defined. We record the answer list OID (whether assigned by Regenstrief
or another organization) and optionally a URL pointing to an external system.
Individual answers are assigned a non-semantic identifier with a “LA” prefix and a mod-10 check digit
(see Appendix C). The answer codes LOINC assigns are unique by lexical string (ignoring capitalization),
and by intention do not distinguish between strings that may have different meanings depending on their
contextual use.
LOINC answer lists are available for viewing in the RELMA program, and are also contained in the
LOINC panels and forms file that is part of the LOINC distribution.
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10.1.1 Null flavors in LOINC answer lists
It is often necessary to indicate that a valid result value is not present. For example, on question on a
questionnaire might have set of response choices and then one choice at the end like “unknown”, “not
applicable”, “not available”, etc. In HL7 standards, these kinds of response values are called null flavors
(see http://hl7-fhir.github.io/v3/NullFlavor/index.html).
There are two techniques for communicating a null flavor. In version 3 messaging, there is a dedicated
nullFlavor attribute that is available for every observation, so these choices are not part of the actual
answer list. In version 2 messaging and FHIR, the convention includes the specific allowed null flavors
within the choices of the answer set. We can see advantages to both approaches.
Within LOINC, we do not want to make different answer lists that vary only by the inclusion or exclusion
of certain null flavors. This is true even for normative answer lists. Thus, our policy is to add specific null
flavors as entries in the answer list where we are aware of their relevance. But, any LOINC answer list
(including normative lists) can be extended or limited by null flavors without violating the intended
conformance that is specified through the binding. So, if a normative answer list included an “unknown”
answer choice, LOINC would not create a separate code for the same observation with “not available” in
the answer list instead of “unknown”. From the perspective of conformance to the LOINC meaning, users
are also free to make such substitutions, insertions, or exclusions of null flavor(s) in the answer list.
10.2 LOINC Parts and Part Hierarchies
In order to support several key aspects of development, Regenstrief has created LOINC Parts, which are a
coded representation of a value for a dimension used to specify a LOINC Term. LOINC Parts support the
translation of LOINC terms into other languages, easy linking of synonyms across many terms, the
creation of hierarchies to group related LOINC terms, and several other functions.
Individual LOINC Parts are assigned a non-semantic identifier with a “LP” prefix and a mod-10 check
digit.
The intended use of the LOINC parts and LOINC part hierarchies are to organize or be constituents of
LOINC terms. As described in the LOINC license, they are not intended for use as a “standalone”
terminology nor apart from LOINC terms.
Furthermore, LOINC parts and LOINC part hierarchies are not strictly managed under the same policies
(e.g. concept orientation, concept permanence) as are LOINC terms.
10.3 Use of the ORDER_OBS field for LOINC terms
LOINC terms can be matched to local test codes that fulfill different roles. For example, a LOINC code
can be used to place an order, to report discrete observations, or in some cases a LOINC term can serve in
both ways.
The purpose of the ORDER_OBS field in the LOINC database is to provide users with an idea of the
intended use of the term by categorizing it as an order only, observation only, or both. A fourth category,
Subset, is used for terms that are subsets of a panel but do not represent a collection of items that is
known to be orderable. Our categorization of a term in this way is not a normative or binding resolution.
That is, it is not a definitional attribute of the term. Rather, it represents Regenstrief’s best approximation
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of how the term is used. (If you feel a term should be categorized a different way, please let us know).
In HL7 messages, the place in the message where the LOINC code is used will indicate what role the
LOINC term is fulfilling. If it is in OBX-3, it is being used as an observation. If it is in OBR-4, it is an
order.
Example of Order Only:
LOINC 34531-4, Blood Type & Crossmatch Panel, is an order for a type and cross, but you would never
expect it to carry an answer (i.e. result value).
Panel terms typically fall in the Order only category.
Example of Observation Only:
LOINC 51890-2, Factor VIII Units given, is a LOINC code that is a discrete observation that would carry
a result of the number of units given to the patient, but a clinician would never place an order for ‘Factor
VIII Units given’.
Example of Both:
LOINC 882-1, ABO & Rh Group in Blood, is a LOINC term that could be used to place an order as well
as report the result of the test (e.g. A Positive).
11 Standardized Assessment Measures
11.1 Introduction
The LOINC committee approved inclusion of standardized assessment measures (e.g., survey
instruments) with version 1.0p. Representing the observations in these assessments within LOINC
required a modest extension of the System axis to include aggregate units of analysis, such as “family”,
and storage of additional attributes within the LOINC database. Bakken32 provides a detailed description
of the methodology for inclusion and evaluation into LOINC and the extensions to the LOINC axes.
The initial corpus of material represented in LOINC came from standardized nursing assessment
instruments, including: Home Health Care Classification (HHC), Quality Audit Marker (QAM), Signs
and Symptoms Checklist for Persons with HIV (HIV-SSC), Living with HIV, and the Omaha System. We
have since expanded the content to cover standardized assessment instruments in many other domains. As
we have added content, we have iteratively refined our modeling. Vreeman et al have published a
summary of our approach and its evolution.33
32
Bakken S, et al. Evaluation of Clinical LOINC (Logical Identifiers, Names, and Codes) for Terminology Model for Standardized
Assessment of Measures. JAMIA 7:2000; 529-538.
33
Vreeman DJ, McDonald CJ, Huff SM. LOINC® - A Universal Catalog of Individual Clinical Observations and Uniform
Representation of Enumerated Collections. Int J Funct Inform Personal Med. 2010;3(4):273-291. Epub 2011 May 23. PubMed PMID:
22899966.
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11.2 Consolidated Health Informatics endorsement
As national interest in using standards for communicating the results of patient assessment instruments
has increased, we have collaborated with members of the Consolidated Health Informatics (CHI)
Disability Workgroup and many others to more fully develop the content and infrastructure to support
patient assessment instruments. LOINC now contains full representations of CMS’s Minimum Data Set
version 2 (MDS) used in nursing homes, CMS’s Outcome and Assessment Information Set (OASIS) used
in home health care, and the Social Security Administration’s Residual Functional Capacity (RFC)
instrument.
Our work with CHI Disability Workgroup has led to the endorsement of Clinical LOINC as a CHI
standard for federally-required assessment (i) questions and answers, and (ii) assessment form that
include functioning and disability content. The recommendations of the CHI Disability Workgroup were
endorsed by the NCVHS and subsequently the HHS Secretary.
11.3 LOINC Representation
The overall organization of the survey instruments and other collections are represented in LOINC using
a nested panel structure consistent with the existing model for laboratory panels. LOINC codes are
created for the individual questions/items within an instrument, as well as for the panels/groups of terms
representing the hierarchical nature of the instrument. We recognize that standardized assessments have
psychometric properties that are essential to their interpretation, and so the data model includes elements
such as the actual question text and allow answer options as attributes of the LOINC observation code.
11.3.1 Naming rules and conventions for names of collection terms (e.g. a panel, survey instrument)
LOINC creates codes for the collection as described in the section on Order Panels (batteries). Typically,
the Property and Scale attributes are a hyphen “-“, because the child elements (questions) vary in these
axes. We create different panel terms for different versions of the same instrument where there are
meaningful changes (e.g. different questions asked, different answer choices, etc). Some assessment
instruments of the same version have different “forms” for various purposes that contain unique
collections of items. For example, the OASIS-C has five unique forms that represent different subsets of
questions that are used at various times: Start of Care, Resumption of Care, Follow-up, Transfer to a
Facility, and Discharge from Agency. LOINC creates different panel terms for each of these forms.
11.3.2 Attributes of the LOINC terms for individual questions or variables
The LOINC table contains fields that store additional attributes relevant to many terms for individual
questions or variables. Examples include the fields that store the exact question text, external copyright
notice, example units, and the HL7 field where the content should be delivered (if Null, presume OBX).
In order to accommodate inclusion of instruments that are copyrighted by a third party, we have added an
External Copyright field to the LOINC table. This field stores the specified terms of use, and additionally,
these terms are visually highlighted in the RELMA program when they appear in search results. We have
only included content in this manner that is consistent with LOINC’s overall aim, so the content allows
free use and distribution for clinical, administrative, and research purposes either with permission or
under applicable terms of use.
LOINC does not usually create terms for information that has a designated field in an HL7 message. But,
in order to create complete sets of items for some instruments we have created LOINC terms for items
such as patient first name. To identify this content, we added an HL7 Field Sub ID to the LOINC table
and indicate the corresponding HL7 place (e.g. PID-5.2).
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11.3.3 Structured answer lists
The questions/items in standardized assessment instruments often have highly specialized, fixed answer
lists. As described above in Section 10.1, we have created a structured representation of the answer lists
for the questions in assessment instruments represented in LOINC.
11.3.4 Attributes of items that vary depending on the parent collection
Some important attributes of a LOINC term for a question or variable may vary when that concept is used
in different assessments or on different forms of the same assessment. For example, “measured body
weight” is a variable of many different assessments. In the context of each instrument, that same concept
could have different local codes, help text, validation rules, or associated branching logic. We therefore
store these attributes at the level of the instance of the item in a particular panel.
11.3.5 Choosing the “display text” for a question or variable
As discussed in the previous sections, we have three fields that can capture the exact display of the
question/item on the form in question. (For some instruments, it can be difficult to determine what exactly
is the question text). The Component of a LOINC term represents the thing or attribute being measured,
and is the default for capturing the item text. However, there are several reasons why the component may
not be the exact item text. The most important ones include: our LOINC naming conventions do not
permit certain characters (e.g. "/" or "?") because of our internal "Part" parsing rules, that some aspects of
the question are modeled in other parts of the formal LOINC name, or that there is some important aspect
to the "thing being measured" (e.g. a look back period of the last 7 days) that is not represented explicitly
on the form for that particular item.
In general, for purposes of displaying the item text as it appears on the instrument, one can follow this
rule:
1. DISPLAY_NAME_FOR_FORM in the FORM_DATA table (RELMA) or FORMS table (CSV
file export) [if populated]. This field provides an override display that is linked to the instance of
the LOINC question code in a particular form. It allows for the same clinical concept to have
slight presentation variances on different forms where those variances have no change in the
concept meaning and accommodates instances where the LOINC naming conventions require
some difference between the item and the LOINC Component. For example, an item might have
the form label of "Body Mass Index (BMI)" but the LOINC Component would simply be "Body
mass index".
If the question or variable is from a survey:
2. SURVEY_QUEST_TEXT in the LOINC table [if populated]. This field is populated when the
variable/item is asked as a question. In some cases, the variable has both a question and a label. In
these cases, the SURVEY_QUEST_TEXT field is populated with both, in the pattern of
[Label].[Question text]. For example, for item J0300 on the MDS version 3 we have "Pain
Presence. Ask resident: ‘Have you had pain or hurting at any time in the last 7 days?’"
3. COMPONENT in the LOINC table. This is the default display.
Else:
4. SHORTNAME in the LOINC table. This field contains a short display name (target is 40
characters or less).
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5. COMPONENT in the LOINC table. This is the default display.
In addition to these fields, some LOINC codes used in survey instruments may have other LOINC name
fields such as a Long Common Name and Consumer Name. These additional names may be useful in
some contexts for these items, be we will still use the above rule to capture the item's representation in the
instrument. Some of the original survey instruments modeled in LOINC may not follow this rule exactly,
in part due to the fact that we did not have the full survey representation model as we do presently.
Ongoing work includes reviewing where modifications may be needed.
11.3.6 Type of Method (6th part) for a question or variable
For variables linked to a defined answer list that come from an external source, it has become our policy
to enter the initial source as the Method. For example, variables first entered for the Minimum Data Set
(MDS) will have a method of MDS. This does not mean that the term cannot be used in any other
contexts, such as other panels or surveys. Many variables from MDS, for example, were later used in the
CARE instrument. These variables in the CARE panel still have a method of MDS. As long as the
defining context of use is understood, the variable can be used in other contexts where the term is exactly
the same, including the answer lists, as the original term.
11.3.7 Time aspect (3rd part) for a question or variable
Beginning with the June 2015 LOINC release, the Time aspect for survey questions that include a
lookback period specify that look back period as the Time rather than using “Pt”. This change was
approved by the LOINC Clinical Committee at the February 2015 Clinical LOINC meeting and will
apply to all new terms moving forward.
At the August 2015 Clinical LOINC meeting, further naming conventions were approved. These
conventions include:
• Using the exact timing given in a validated survey question as the Time value (i.e., for questions
with a 7 day lookback period, using “7D” for Time rather than “1W”)
• Adding “Lifetime” as a possible Time value
• For questions with a lookback range, using the longer end of the range for Time (e.g., if the
question asks “In the last 2-6 months…”, the Time value will be “6Mo”).
As of LOINC version 2.54, nearly all of the existing survey instrument terms that include a look back
period have an updated Time part, and we will continue to make these changes moving forward for any
terms that were not updated for the 2.54 release.
11.4 Assessment Content in the LOINC Distribution
All of the assessment content is included within RELMA. Beginning with LOINC version 2.26 (January
2009), an export of panels and forms content has been available as a separate download in the LOINC
release available from http://loinc.org. This spreadsheet contains separate worksheets for the three files
defining the full assessment content:
1. The hierarchical structure (parent/child relationships) and panel-specific attributes
2. An extract of the main LOINC Table for all of the terms in the set
3. The structured answer list for each LOINC variable term in the set
The full set of all of the panels and forms content, as well as several domain-specific subsets, are
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available for download from the LOINC website.
12 Editorial Policies and Procedures
12.1 Concept orientation and LOINC name changes
LOINC is a concept-based terminology, which means that it provides a way of naming classes of things
that exist in the real world. Each concept (term) is given an identifier and a fully-specified name. Other
attributes, including other names such as a Short Name and Long Common Name, are also provided in
the LOINC database. The concept is anchored by the LOINC code, not by the particular strings in the
formal name we happen to use to explain the code. It is certainly not possible to convey all of the
subtleties that exist in the world with formal machinery alone, which is why we are also working very
hard to include narrative text descriptions with each term that further elaborate and explain the concept.
In a complex, organic terminology like LOINC, name changes and modifications are unavoidable for
many reasons. Since its inception, LOINC has maintained a set of editorial policies that guide our
adherence to this concept-oriented ideal even as the terminology evolves over time. An over-arching
policy is that we can change the name (i.e. the human-readable representation of the concept) in any way
that does not change the meaning of the concept. In other words, a modification is allowable and valid if
it is still an unambiguous reference to a class of things in the real world.
For example, two different numbering systems have been used to identify the serotypes of Streptococcus
pneumoniae, which are important in gauging the coverage of polyvalent pneumonia vaccines. The U.S.
system uses only numbers while the Danish system includes numbers and letters. For a period of time,
LOINC term names were split and used a mixture of the Danish and U.S. identifiers, which was
inconsistent and confusing. To clarify, we converted the few Danish serotype identifiers to their
corresponding U.S. serotype identifiers (and included the Danish identifiers as synonyms). This was not a
fundamental change to the underlying concept, but rather just the particular labels used to express it.
Not all situations are crystal clear, so our general policy is to seek as much input as is feasible, and
typically such cases are brought for discussion to the LOINC Committee.
12.2 Classification of LOINC term status
LOINC development follows best practices for terminology system development by never reusing or
deleting codes. If a LOINC term is identified as erroneous or a duplicate of a previous term it is flagged
as “deprecated” in the database, but the record is not removed. Changes in concept status are made very
judiciously.
Prior to the LOINC version 2.31 release (June 2010), we identified such deprecated terms by populating
the STATUS field of the database with “DEL” and wherever possible identified superseding concepts in
the MAP_TO field of the LOINC Table. Active (non-deprecated) records had no value (null) in the
STATUS field. Based on new use cases and input from the LOINC community, LOINC 2.31
implemented an expansion to that classification. The presently supported values for term status, with the
definition and implications for use, are:
ACTIVE
TRIAL
DISCOURAGED
Concept is active. Use at will.
Concept is experimental in nature. Use with caution as the concept and
associated attributes may change.
Concept is not recommended for current use. New mappings to this
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DEPRECATED
concept are discouraged; although existing mappings may continue to be
valid in context. Wherever possible, the superseding concept is indicated
in the MAP_TO field of the MAP_TO Table (see Appendix A, Table
31b) and should be used instead.
Concept is deprecated. Concept should not be used, but it is retained in
LOINC for historical purposes. Wherever possible, the superseding
concept is indicated in the MAP_TO field of the MAP_TO Table (see
Appendix A, Table 31b) and should be used both for new mappings and
updating existing implementations.
Furthermore, LOINC 2.31 added two new fields:
STATUS_REASON
STATUS_TEXT
Classification of the reason for concept status. This field will be Null for
ACTIVE concepts, and optionally populated for terms in other statuses
where the reason is clear. DEPRECATED or DISCOURAGED terms
may take values of: AMBIGUOUS, DUPLICATE, or ERRONEOUS.
Explanation of concept status in narrative text. This field will be Null for
ACTIVE concepts, and optionally populated for terms in other statuses.
Our initial implementation of these new concept status values populated the STATUS field with
“ACTIVE” or “DEPRECATED” based on their existing status and have identified a limited set of terms
that have been designated “DISCOURAGED” or “TRIAL”.
The principal reason identifying terms as DISCOURAGED is where we have strong inclinations that a
particular term is no longer valid given current practice. For example, we have flagged as
DISCOURAGED several lutropin terms with Properties consistent with mass or molar units because all
lutropin sources that we could reach report concentrations in international units (IU) per volume and the
drug lutropin is prescribed in terms of international units per volume. To avoid help confusion on the part
of mappers, the DISCOURAGED status steers them away from these terms to the more likely candidates.
The principal reason for identifying terms as TRIAL is a very constrained circumstance, such as when the
source of the term is still equivocating. This has been illustrated in our work to create a LOINC
representation of federally-required patient assessment instruments. Here, the item meaning is defined in
the context of use within that instrument. We have been fortunate to work with assessment developers in
the early stages of instrument development. This is advantageous because it enables the codes to be
included in data specifications and documents as they are developed, but we are in the position of creating
codes and names for data elements whose attributes are still in flux. As the instrument evolves, the
specific representation of the item (question) or answer options on the form may change. Ultimately, the
representation will be settled by an authoritative body (such as CMS) and they are intended for use in one
context – the official release of the instrument. Identifying these terms as TRIAL allows us to include
them in the public distribution while clearly flagging their “pending” status. Once the final concept
representation has been determined, terms initially labeled TRIAL would be reclassified as ACTIVE (or
perhaps in rare circumstances DEPRECATED or even rarer DISCOURAGED).
In LOINC 2.42, the MAP_TO field of the LOINC Table was removed and replaced with a separate
MAP_TO table. The original MAP_TO field was created to store a single replacement LOINC term
number for when a LOINC was deprecated. We later learned that there were times when there was more
than one possible replacement term, depending on certain conditions. To address this problem we created
a new MAP_TO table that was first released with version 2.34. The original MAP_TO field was retained
for a few releases, but was removed from the LOINC Table in version 2.42. See Appendix A, Table 31b
for information about the MAP_TO table.
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12.3 Concept persistence and term deprecation
LOINC codes are never reused or deleted, and the concept meaning is persistent over time despite the fact
that there may be modifications to the name (as described above). If we discover that a LOINC term’s
meaning is a duplicate of another existing term or it is somehow erroneous, it will be given a status of
DEPRECATED but not removed from the database.
In the past, when we encountered duplicate terms (i.e. terms that had different names but meant the same
thing), our general policy was to deprecate the newest term. Many times, this convention worked well
because the older term was more likely to have been incorporated into user’s systems through mappings,
etc. However, this was not always the case. Sometimes, the new term had the clearer, more recognizable
label and thus it was most likely the most mapped-to term.
Therefore, our current policy is to make the change to require (in our estimation) the least amount of remapping for existing users.
13 Recommendations for Best Practices in Using and Mapping to
LOINC
13.1 Business rules for users mapping their local panels to LOINC panels
Through discussion with the ACLA, the S&I Framework aLOINC Order Code Initiative, and others, the
LOINC Committee has vetted a set of business rules to help LOINC users understand how to compare
their panels to a LOINC panel. These rules help clarify what variation is allowed within the LOINC panel
definition that still constitutes a “match” for their panel. In these rules, we use “element” to mean a child
LOINC that is a member of the panel definition.
13.1.1 Must contain all of the required elements
To establish equivalence (e.g. for mapping), a user panel must contain all of the required elements of a
LOINC panel. Some of the other business rules define allowable substitutions, but the general rule is that
all required elements must be present in the user panel.
13.1.2 No extra primary measurements
A user panel cannot be considered equivalent to a LOINC panel term if it contains additional primary
measured tests that are not part of the LOINC panel definition.
13.1.3 Optional elements are optional
A user panel can be considered equivalent to a LOINC panel term whether or not it contains the elements
marked as optional in the LOINC panel definition.
13.1.4 Substitutions related to Method
Panel elements that do not contain a Method specification (i.e. the Type of Method part is null) can be
treated as a “representative” term that a user could replace with another LOINC term that differed only by
specification of method.
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For example, LOINC contains an adenovirus panel (LOINC # 55160-6 Adenovirus IgG and IgM panel Serum) with two elements that lack method specification:
13914-7
5042-7
Adenovirus IgG Ab [Units/volume] in Serum
Adenovirus IgM Ab [Units/volume] in Serum
If a user had a local panel that was similar but had instead mapped to terms that specified the method of
EIA, they may wonder whether their panel was equivalent to the panel in LOINC. Using this business
rule, the answer is yes. Either or both of the methodless LOINC panel elements could be replaced by
these method-specific LOINC terms that are equivalent on the other attributes:
51822-5
51823-3
Adenovirus IgG Ab [Units/volume] in Serum by Immunoassay
Adenovirus IgM Ab [Units/volume] in Serum by Immunoassay
However, when a panel element measures an analyte by a particular method, then the LOINC term
reported for that analyte would have to be done by that method. Neither replacement by a methodless
term nor by a different method would be allowed.
13.1.5 Substitutions for mass versus substance Properties
LOINC defines different terms that distinguish between mass-based and substance-based
(moles/milliequivalents) measures for a single analyte. Different jurisdictions vary in whether they favor
reporting in mass units (e.g. mg/dL) or molar units (e.g. mmol/L) for certain analytes.
In order to promote the international reuse of panels, the LOINC Committee has agreed (at its June 2015
meeting) to allow users to substitute panel elements that a) agree on all other LOINC parts, and b) contain
an analogous molar Property to a reference element with a mass Property or vice versa.
To illustrate, panel element terms with the property of mass concentration (MCnc) could be replaced by
substance concentration (SCnc) terms, mass rate (MRat) terms could be replaced by substance rate
(SRat), terms etc. For example, in the Lipid panel with direct LDL - Serum or Plasma (LOINC # 576983) a user could make substitutions as below and still have a comparable panel:
Reference term: 2093-3
Substitute term: 14647-2
Cholesterol [Mass/volume] in Serum or Plasma
Cholesterol [Moles/volume] in Serum or Plasma
Reference term: 2571-8
Substitute term: 14927-8
Triglyceride [Mass/volume] in Serum or Plasma
Triglyceride [Moles/volume] in Serum or Plasma
And so forth.
13.1.6 No substitutions of quantitative for qualitative (and vice versa)
A quantitative panel element (e.g. one that has a Scale of Qn) cannot be replaced by a qualitative term
(e.g. one that has a scale of Ord) and have the panel be considered equivalent. Likewise, qualitative terms
cannot be replaced by quantitative terms in the panel definition.
13.1.7 Pay attention to reflex components
LOINC defines different panels for testing that has reflex elements from ones that do not. Thus, users
104
must be aware of the test(s) done as a reflex both in their local panels and in the LOINC definition. The
reflex test(s) can be a single test, a group of tests, or a test panel. A user panel is comparable to the
LOINC panel if the specification of reflex testing is the same.
13.1.8 Special case of differential counts (including conventions for not reporting zero counts)
Panels, like blood differential counts and urinalyses, for which zero counts (e.g. for the % of blast cells)
are usually not reported explicitly present a special case. These are included in the panel definition but are
marked as conditional (C) to signal that under some circumstances (e.g., when they have a value of zero),
they are not reported. Differential counts present another problem in that a given cell type could be
reported as a fraction of the total WBC and/or as an absolute count, so both species are included in the
panel for differential counts, but as discussed above, both are not required in the report.
13.1.9 Panels with only narrative definitions of the elements they should contain
As described above, in certain special cases such as public health and veterinary testing, LOINC may
define a panel term by a narrative definition rather than enumerating the set of child elements. In such
cases, the user must read the definition and use their professional judgment as to whether or not their local
panel is comparable to the LOINC panel.
13.2 Examples of applying the business rules for users mapping their local panels to
LOINC panels
13.2.1 Comparison Panel: Varicella zoster virus IgG and IgM panel - Serum (LOINC # 45063-5)
This user-defined panel is considered comparable since the component tests are the same and it is
acceptable to use method- specific LOINC codes for panels defined with methodless LOINC codes.
Elements of LOINC Panel
LOINC_NUM
Long Common Name
R/O/C
8048-1
Varicella zoster virus IgM Ab [Units/volume] in Serum
R
8047-3
Varicella zoster virus IgG Ab [Units/volume] in Serum
R
Elements of User-defined Panel
LOINC_NUM
Long Common Name
5404-9
Varicella zoster virus IgM Ab [Units/volume] in Serum by Immunoassay
5403-1
Varicella zoster virus IgG Ab [Units/volume] in Serum by Immunoassay
13.2.2 Comparison Panel: Creatine kinase panel - Serum or Plasma (LOINC # 24335-2)
This user-defined panel is not considered to be comparable since it includes 2 additional measured
components that are not in the LOINC Panel.
NOTE: The inclusion of an Optional component in the LOINC Panel does not have a bearing on the
comparability of the user-defined panel.
105
LOINC_NUM
Long Common Name
R/O/C
2157-6
Creatine kinase [Enzymatic activity/volume] in Serum or Plasma
R
20569-0
Creatine kinase.MB/Creatine kinase.total in Serum or Plasma
R
9642-0
Creatine kinase.BB/Creatine kinase.total in Serum or Plasma
R
9643-8
Creatine kinase.MM/Creatine kinase.total in Serum or Plasma
R
5912-1
Creatine kinase isoenzymes [interpretation] in Serum or Plasma
O
LOINC_NUM
Long Common Name
2157-6
Creatine kinase [Enzymatic activity/volume] in Serum or Plasma
20569-0
Creatine kinase.MB/Creatine kinase.total in Serum or Plasma
9642-0
Creatine kinase.BB/Creatine kinase.total in Serum or Plasma
9643-8
Creatine kinase.MM/Creatine kinase.total in Serum or Plasma
26020-8
Creatine Kinase.macromolecular type 2/Creatine kinase.total in Serum or Plasma
26019-0
Creatine Kinase.macromolecular type 1/Creatine kinase.total in Serum or Plasma
13.2.3 Comparison Panel: Drugs of abuse 5 panel - Urine by Screen method (LOINC # 65750-2)
This user-defined panel is considered to be comparable since the components use the same methodspecific LOINC terms and the additional test is a non-measured component (i.e. it is a variable provided
by the requester that is echoed back with the results).
LOINC_NUM
Long Common Name
R/O/C
19261-7
Amphetamines [Presence] in Urine by Screen method
R
14314-9
Benzoylecgonine [Presence] in Urine by Screen method
R
18282-4
Cannabinoids [Presence] in Urine by Screen method
R
19295-5
Opiates [Presence] in Urine by Screen method
R
19659-2
Phencyclidine [Presence] in Urine by Screen method
R
LOINC_NUM
Long Common Name
19261-7
Amphetamines [Presence] in Urine by Screen method
14314-9
Benzoylecgonine [Presence] in Urine by Screen method
18282-4
Cannabinoids [Presence] in Urine by Screen method
19295-5
Opiates [Presence] in Urine by Screen method
19659-2
Phencyclidine [Presence] in Urine by Screen method
41395-5
Collection date of Urine
106
13.3 Querying LOINC and creating intensional value set definitions based on
LOINC database structure
Specifications that contain queries meant to be run on the LOINC distribution or that contain intensional
value set definitions should be expressed with the LOINC properties contained in Appendix A - LOINC
Database Structure. The available LOINC properties are the items listed in the ‘Field Name’ column of
that table. These names, and their spellings, are the official property names. For example, specifying the
set of LOINC terms with a scale of document would reference the LOINC property “SCALE_TYP” and
its value of “DOC”.
In addition, for those LOINC codes that are part of the Document Ontology, there are currently five
additional properties that may be used in property-based Value Set Definition components:
•
•
•
•
•
Document.Kind
Document.TypeOfService
Document.Setting
Document.Role
Document.SubjectMatterDomain
These Document Ontology properties are currently published in the auxiliary Document Ontology File
(available as a separate download from the LOINC website), and will likely be extended in the future.
They will always be the unique values in the PartTypeName column of the Document Ontology File. All
properties will have string values that may be used for the property value part of the definition.
13.4 LOINC term names in HL7 messages
Messaging standards like HL7 typically use a triplet <identifier code>^<descriptive text>^<coding
system> for fields that contain coded entries, such as the OBX-3 Observation Identifier field. Given that
LOINC now produces at least 3 names for each term (i.e., the six-part Fully-Specified Name, Short
Name, and Long Common Name), users have wondered which LOINC name they should use in the
<descriptive text> part of that field (or the equivalent displayName attribute in HL7 V3). In general, we
recommend the use of the Long Common Name because they are probably the most understandable to
human readers. However, the Long Common Names can be quite long and some systems may not be able
to accommodate them. In these cases, we would recommend the use of the Short Name because they
would fit within the space allocated by most reporting systems, could potentially work as a column name
on a flow sheet, and mostly use common acronyms. Using the Fully-Specified Name (e.g. a colonseparated aggregate of the six part name) is generally not recommended because they are not as human
friendly and contain more instances of ‘reserved characters’ like “^” and “&”, which would need to be
properly escaped in the message.
Furthermore, we recommend the simultaneous communication of the sender’s local code and local name
(in addition to the LOINC code and name) as allowed in the messaging structure to facilitate debugging
and detection of mis-mappings.
13.5 Updating to new versions of LOINC
At the December 2015 Lab LOINC Committee meeting. Regenstrief and the LOINC Committee
approved the following best practice:
107
We recommend that users update to the current version of LOINC within 90 days of its publication.
13.6 Using a URI to identify LOINC concepts as resources in RDF
The subject of an RDF statement is a uniform resource identifier (URI), or a blank node. Some users have
asked for an approved convention for referring to LOINC concepts in RDF. After discussion at the
Clinical LOINC Committee meeting in August 2015, we agreed to the following patterns:
For LOINC terms:
http://loinc.org/rdf/{LOINC code}
e.g. http://loinc.org/rdf/2352-3
For LOINC parts:
http://loinc.org/rdf/{LOINC Part code}
e.g. http://loinc.org/rdf/LP6990-8
In our current platform, URLs of these patterns resolve to the concept details pages (as used by
search.loinc.org and RELMA).
108
Appendix A - LOINC Database Structure
Table 31a: LOINC Table Structure
Field Name
Type
Width
1. LOINC_NUM
Text
10
2. COMPONENT
Text
255
3. PROPERTY
Text
30
4. TIME_ASPCT
Text
15
5. SYSTEM
Text
100
6. SCALE_TYP
Text
30
7. METHOD_TYP
Text
50
8. CLASS
Text
20
Description
The unique LOINC Code is a string in the format of
nnnnnnnn-n.
First major axis-component or analyte
Second major axis-property observed (e.g., mass vs.
substance)
Third major axis-timing of the measurement (e.g., point in
time vs 24 hours)
Fourth major axis-type of specimen or system (e.g., serum vs
urine)
Fifth major axis-scale of measurement (e.g., qualitative vs.
quantitative)
Sixth major axis-method of measurement
An arbitrary classification of the terms for grouping related
observations together. The current classifications are listed in
Table 32. We present the database sorted by the class field
within class type (see field 23). Users of the database should
feel free to re-sort the database in any way they find useful,
and/or to add their own classifying fields to the database.
The content of the laboratory test subclasses should be obvious
from the subclass name.
9. VersionLastChanged
Text
10
10. CHNG_TYPE
Text
3
Memo
-
12. STATUS
Text
11
13. CONSUMER_NAME
Text
255
11. DefinitionDescription
109
The LOINC version number in which the record has last
changed. For new records, this field contains the same value as
the loinc.FirstPublishedRelease field.
Change Type Code
DEL = delete (deprecate)
ADD = add
NAM = change to Analyte/Component (field #2);
MAJ = change to name field other than #2 (#3 - #7);
MIN = change to field other than name
UND = undelete
Narrative text that describes the LOINC term taken as a whole
(i.e., taking all of the parts of the term together) or relays
information specific to the term, such as the context in which
the term was requested or its clinical utility.
ACTIVE = Concept is active. Use at will.
TRIAL = Concept is experimental in nature. Use with caution
as the concept and associated attributes may change.
DISCOURAGED = Concept is not recommended for current
use. New mappings to this concept are discouraged; although
existing may mappings may continue to be valid in context.
Wherever possible, the superseding concept is indicated in the
MAP_TO field in the MAP_TO table (see Table 31b) and
should be used instead.
DEPRECATED = Concept is deprecated. Concept should not
be used, but it is retained in LOINC for historical purposes.
Wherever possible, the superseding concept is indicated in the
MAP_TO field (see Table 31b) and should be used both for
new mappings and updating existing implementations.
An experimental (beta) consumer friendly name for this item.
The intent is to provide a test name that health care consumers
will recognize; it will be similar to the names that might
appear on a lab report and is not guaranteed to be unique
because some elements of the LOINC name are likely to be
omitted. We will continue to modify these names in future
release, so do not expect it to be stable (or perfect). Feedback
is welcome.
14. CLASSTYPE
Number
-
15. FORMULA
Text
255
16. SPECIES
Text
20
17. EXMPL_ANSWERS
Memo
-
18. SURVEY_QUEST_TEXT
Memo
-
19. SURVEY_QUEST_SRC
Text
50
20. UNITSREQUIRED
Text
1
21. SUBMITTED_UNITS
Text
30
22. RELATEDNAMES2
Memo
-
23. SHORTNAME
Text
40
24. ORDER_OBS
Text
15
25. CDISC_COMMON_TESTS
Text
1
26. HL7_FIELD_SUBFIELD_ID
Text
50
Memo
-
28. EXAMPLE_UNITS
Text
255
29. LONG_COMMON_NAME
Text
255
Memo
-
Text
255
27. EXTERNAL_COPYRIGHT_NOTICE
30. UnitsAndRange
31. DOCUMENT_SECTION
110
1=Laboratory class; 2=Clinical class; 3=Claims attachments;
4=Surveys
Contains the formula in human readable form, for calculating
the value of any measure that is based on an algebraic or other
formula except those for which the component expresses the
formula. So Sodium/creatinine does not need a formula, but
Free T3 index does.
Codes detailing which non-human species the term applies to.
If blank, “human” is assumed.
For some tests and measurements, we have supplied examples
of valid answers, such as “1:64”, “negative @ 1:16”, or “55”.
Verbatim question from the survey instrument
Exact name of the survey instrument and the item/question
number
Y/N field that indicates that units are required when this
LOINC is included as an OBX segment in a HIPAA
attachment
Units as received from person who requested this LOINC
term.
This field was introduced in version 2.05. It contains
synonyms for each of the parts of the fully specified LOINC
name (component, property, time, system, scale, method). It
replaces #8, Relat_NMS.
Introduced in version 2.07, this field contains the short form of
the LOINC name and is created via a table driven algorithmic
process. The short name often includes abbreviations and
acronyms.
Defines term as order only, observation only, or both. A fourth
category, Subset, is used for terms that are subsets of a panel
but do not represent a package that is known to be orderable.
We have defined them only to make it easier to maintain
panels or other sets within the LOINC construct. This field
reflects our best approximation of the terms intended use; it is
not to be considered normative or a binding resolution.
“Y” in this field means that the term is a part of subset of
terms used by CDISC in clinical trials.
A value in this field means that the content should be delivered
in the named field/subfield of the HL7 message. When NULL,
the data for this data element should be sent in an OBX
segment with this LOINC code stored in OBX-3 and with the
value in the OBX-5.
External copyright holders copyright notice for this LOINC
code.
This field is populated with a combination of submitters units
and units that people have sent us. Its purpose is to show users
representative, but not necessarily recommended, units in
which data could be sent for this term.
This field contains the LOINC name in a more readable format
than the fully specified name. The long common names have
been created via a table driven algorithmic process. Most
abbreviations and acronyms that are used in the LOINC
database have been fully spelled out in English.
Units of measure (expressed using UCUM units) and normal
ranges for physical quantities and survey scores. Intended as
tailorable starter sets for applications that use LOINC forms as
a way to capture data. Units are separated from normal ranges
by a colon (:) and sets of unit:normal range pairs are separated
by a semi-colon (;). Syntax for the normal range includes
square brackets, which mean that the number adjacent to the
bracket is included, and parentheses, which means that the
number itself is not included. For example, [2,4] means “two
to four”, while [2,4) means “two to less than four” and (2,4)
means “between two and four but does not include two and
four”.
Classification of whether this LOINC code can be used a full
document, a section of a document, or both. This field was
created in the context of HL7 CDA messaging, and populated
in collaboration with the HL7 Structured Documents Work
Group.
32. EXAMPLE_UCUM_UNITS
Text
255
33. EXAMPLE_SI_UCUM_UNITS
Text
255
34. STATUS_REASON
Text
9
35. STATUS_TEXT
Memo
-
36. CHANGE_REASON_PUBLIC
Memo
-
37. COMMON_TEST_RANK
Number
-
38. COMMON_ORDER_RANK
Number
-
39. COMMON_SI_TEST_RANK
Number
-
40. HL7_ATTACHMENT_STRUCTURE
Text
15
41. EXTERNAL_COPYRIGHT_LINK
Text
255
42. PanelType
Text
255
43. AskAtOrderEntry
Text
255
44. AssociatedObservations
Text
50
111
The Unified Code for Units of Measure (UCUM) is a code
system intended to include all units of measures being
contemporarily used in international science, engineering, and
business. (www.unitsofmeasure.org ) This field contains
example units of measures for this term expressed as UCUM
units.
The Unified Code for Units of Measure (UCUM) is a code
system intended to include all units of measures being
contemporarily used in international science, engineering, and
business. (www.unitsofmeasure.org) This field contains
example units of measures for this term expressed as SI
UCUM units.
Classification of the reason for concept status. This field will
be Null for ACTIVE concepts, and optionally populated for
terms in other status where the reason is clear. DEPRECATED
or DISCOURAGED terms may take values of:
AMBIGUOUS, DUPLICATE, or ERRONEOUS.
Explanation of concept status in narrative text. This field will
be Null for ACTIVE concepts, and optionally populated for
terms in other status.
Detailed explanation about special changes to the term over
time.
Ranking of approximately 2000 common tests performed by
laboratories in USA.
Ranking of approximately 300 common orders performed by
laboratories in USA.
Corresponding SI terms for 2000 common tests performed by
laboratories in USA
This field will be populated in collaboration with the HL7
Attachments Work Group as described in the HL7 Attachment
Specification: Supplement to Consolidated CDA Templated
Guide. Text will either be STRUCTURED or
UNSTRUCTURED for relevant terms. The STRUCTURED
terms are the allowed document type codes in the
Consolidated CDA (C-CDA) Implementation guide.
UNSTRUCTURED terms are approved by the HL7
Attachments WG for transmission using the Unstructured
Document template of the C-CDA.
For terms that have a third party copyright, this field is
populated with the COPYRIGHT_ID from the Source
Organization table (see Table 31c below). It links a external
copyright statement to a term.
Describes a panel as a "Convenience group", "Organizer", or
"Panel". A "Panel" is an enumerated set of terms that are used
together in direct clinical care. The package would typically be
thought of as a single orderable item that contains a set of
reported observations. A "Convenience group" is an
enumerated set of terms used for a common purpose, but not
typically orderable as a single unit. An "Organizer" is a
subpanel (i.e. a child) within another panel that is only used to
group together a set of terms, but is not an independently used
entity. They often represent a header in a form, or serve as a
navigation concept.
A multivalued field, semicolon delimited list of LOINC codes
that represent optional Ask at Order Entry (AOE) observations
for a clinical observation or laboratory test. A LOINC term in
this field may represent a single AOE observation or a panel
containing several AOE observations.
A multi-valued, semicolon delimited list of LOINC codes that
represent optional associated observation(s) for a clinical
observation or laboratory test. A LOINC term in this field may
represent a single associated observation or panel containing
several associated observations.
Table 31b: MAP_TO Table Structure
Field Name
Type
Width
1. LOINC
Text
10
2. MAP_TO
Text
10
Memo
-
3. COMMENT
Description
The deprecated term to which the replacement term(s) apply.
A replacement term that is to be used in place of the
deprecated or discouraged term.
Narrative text that explains the rational for using the
recommended replacement term.
Table 31c: Source Organization Table Structure
Field Name
Type
Width
1. COPYRIGHT_ID
Text
255
Used in the LOINC table as a foreign key.
2. NAME
Text
255
3. COPYRIGHT
Memo
-
4. TERMS_OF_USE
Memo
-
Name of the organization or institution.
Copyright notice to be displayed for the organization or
institution.
Terms of use text for an external source.
Text
255
5. URL
112
Description
URL link to the reference.
Appendix B - Classes
Table 32a: Clinical Term Classes
Abbreviation
Clinical Term Class
ADMIN
Administrative
ADMIN.DEMOG
Demographic observations
APTA
American Physical Therapy Association
ART
Antiretroviral therapy
BDYCRC.ATOM
Body circumference atomic
BDYCRC.MOLEC
Body circumference molecular
BDYHGT.ATOM
Body height atomic
BDYHGT.MOLEC
Body height molecular
BDYSURF.ATOM
Body surface atomic
BDYTMP.ATOM
Body temperature atomic
BDYTMP.MOLEC
Body temperature molecular
BDYTMP.TIMED.MOLEC
Body temperature timed molecular
BDYWGT.ATOM
Body weight atomic
BDYWGT.MOLEC
Body weight molecular
BP.ATOM
Blood pressure atomic
BP.CENT.MOLEC
Blood pressure central molecular
BP.MOLEC
Blood pressure molecular
BP.PSTN.MOLEC
Blood pressure positional molecular
BP.TIMED.MOLEC
Blood pressure timed molecular
BP.VENOUS.MOLEC
Blood pressure venous molecular
CARD.PROC
Cardiac procedures
CARD.RISK
Cardiac Risk Scales Framingham
CARD.US
Cardiac ultrasound (was US.ECHO)
CARD.US.DICOM
DICOM Simplified Adult Echo Report concepts
CARDIO-PULM
Cardiopulmonary
CLIN
Clinical NEC (not elsewhere classified)
DENTAL
Dental
DEVICES
Medical devices
DOC.ADMIN
Administrative documents
DOC.ADMIN.LEGAL
Legal Administrative documents
DOC.EPSOS
Smart Open Services for European Patients (epSOS) documents
DOC.MISC
Miscellaneous documentation
DOC.ONTOLOGY
Document Ontology
DOC.PUBLICHEALTH
Public health documentation
DOC.QUALITY
Quality documents
DOC.REF
Referral documentation
DOC.REF.CTP
Clinical trial protocol document
DOCUMENT.REGULATORY
Regulatory documentation
ED
Emergency (DEEDS)
EKG.ATOM
Electrocardiogram atomic
EKG.IMP
Electrocardiogram impression
EKG.MEAS
Electrocardiogram measures
ENDO.GI
Gastrointestinal endoscopy
EYE
Eye
113
EYE.ANGIO.NEI
NEI eyeGENE’s angiography concepts
EYE.CONTACT_LENS
Ophthalmology contact lens
EYE.EOG.NEI
NEI eyeGENE’s electrooculogram concepts
EYE.ERG.NEI
NEI eyeGENE’s electroretinogram concepts
EYE.GLASSES
Ophthalmology glasses: Lens manufacturer (LM) & Prescription
EYE.HETEROPHORIA
Ophthalmology heterophoria
EYE.HX.NEI
NEI eyeGENE’s eye history concepts
EYE.OCT
Ophthalmology Optical Coherence Tomography (OCT)
EYE.OCT.NEI
NEI eyeGENE’s optical coherence tomography concepts
EYE.PX
Ophthalmology physical findings
EYE.PX.NEI
NEI eyeGENE’s eye physical exam concepts
EYE.REFRACTION
Ophthalmology refraction
EYE.REFRACTION.NEI
NEI eyeGENE’s refraction concepts
EYE.RETINAL_RX
Ophthalmology treatments
EYE.SLITLAMP.NEI
NEI eyeGENE’s slit lamp biomicroscopy concepts
EYE.TONOMETRY
Ophthalmology tonometry
EYE.TONOMETRY.NEI
NEI eyeGENE’s tonometry concepts
EYE.US
Ophthalmology ultrasound
EYE.VISUAL_FIELD
Ophthalmology visual field
EYE.VISUAL_FIELD.NEI
NEI eyeGENE’s visual field concepts
FUNCTION
Functional status (e.g., Glasgow)
GEN.US
General ultrasound
H&P.HX
History
H&P.PX
Physical
H&P.SURG PROC
Surgical procedure
HEMODYN.ATOM
Hemodynamics anatomic
HEMODYN.MOLEC
Hemodynamics molecular
HL7.CCDA
HL7 Consolidated Clinical Document Architecture
HRTRATE.ATOM
Heart rate atomic
HRTRATE.MOLEC
Heart rate molecular
HRTRATE.PSTN.MOLEC
Heart rate positional molecular
HRTRATE.TIMED.MOL
Heart rate timed molecular
IO.TUBE
Input/Output of tube
IO_IN.ATOM
Input/Output atomic
IO_IN.INFUS
Infusion pump intake measures
IO_IN.MOLEC
Input/Output molecular
IO_IN.SUMMARY
Input/Output summary
IO_IN.TIMED.MOLEC
Input/Output timed molecular
IO_IN_SALTS+CALS
Input/Output electrolytes and calories
IO_OUT.ATOM
Input/Output atomic
IO_OUT.MOLEC
Input/Output molecular
IO_OUT.TIMED.MOLE
Input/Output timed molecular
NEMSIS
National EMS Information System data
NEONAT
Neonatology variables
NEURO
Neurology
NUTRITION&DIETETICS
Nutrition and Dietetics
OB.US
Obstetric ultrasound
OBGYN
Obstetric/Gynecology
ONCOLOGY
Oncology
114
PANEL.APTA
American Physical Therapy Association panel
PANEL.ART
Antiretroviral therapy order set
PANEL.BDYTMP
Body temperature order set
PANEL.BP
Blood pressure order set
PANEL.CARDIAC
Cardiac studies order set
PANEL.CLIN
Clinical NEC (not elsewhere classified) set
PANEL.CV
Cardiovascular order set
PANEL.DEVICES
Medical devices order set
PANEL.DOC
Documents panels
PANEL.ED
Emergency (DEEDS) order set
PANEL.EYE
Ophthalmology panels
PANEL.FUNCTION
Function order set
PANEL.H&P
History & Physical order set
PANEL.HL7.CCDA
HL7 Consolidated Clinical Document Architecture set
PANEL.IEEE ROSETTA
IEEE Rosetta panels
PANEL.IO
Input/Output order set
PANEL.NEMSIS
National EMS Information System data set
PANEL.NEONAT
Neonatal measures order set
PANEL.NUTRITION&DIET
Nutrition and dietetics panel
PANEL.OB.US
Obstetrical order set
PANEL.ONCO
Oncology set
PANEL.PATIENT SAFETY
Patient safety order set
PANEL.PHENX
PhenX Panel
PANEL.PHR
Public health record order set
PANEL.PULM
Pulmonary order set
PANEL.RAD
Radiology order set
PANEL.SURG
Surgery panel
PANEL.TUMRRGT
Tumor registry order set
PANEL.US.URO
Urology ultrasound order set
PANEL.VACCIN
Vaccination order set
PANEL.VITALS
Vital signs order set
PATIENT SAFETY
Patient safety
PHENX
PhenX
PUBLICHEALTH
Public Health
PULM
Pulmonary ventilator management
RAD
Radiology
RESP.ATOM
Respiratory atomic
RESP.MOLEC
Respiratory molecular
RESP.TIMED.MOLEC
Respiratory timed molecular
SKNFLD.MOLEC
Skinfold measurements molecular
SURG
Surgery
TRAUMASKNFLD.MOLEC
Trauma Skinfold measurements molecular
TRNSPLNT.ORGANTRAUMA
Organ transplant Trauma
TUMRRGTTRNSPLNT.ORGAN
Tumor registry (NAACCR)Organ transplant
US.UROTUMRRGT
Urological ultrasound Tumor registry (NAACCR)
VACCINUS.URO
Vaccinations Urological ultrasound
VOLUME.MOLECVACCIN
Volume (specimen) molecular Vaccinations
VOLUME.MOLEC
Volume (specimen) molecular
TRAUMA
Trauma
115
TRNSPLNT.ORGAN
Organ transplant
TUMRRGT
Tumor registry (NAACCR)
US.URO
Urological ultrasound
VACCIN
Vaccinations
VOLUME.MOLEC
Volume (specimen) molecular
Table 32b: Laboratory Term Classes
Abbreviation
Laboratory Term Class
ABXBACT
Antibiotic susceptibilities
ALLERGY
Response to antigens
BLDBK
Blood bank
CARDIO-PULM
Cardiopulmonary
CELLMARK
Cell surface models
CHAL
Challenge tests
CHAL.ROUTINE
Routine challenge tests
CHALSKIN
Skin challenge tests
CHEM
Chemistry
CHEM.ESOTERIC
Esoteric chemistry tests
COAG
Coagulation study
CYTO
Cytology
DRUG/TOX
Drug levels & Toxicology
DRUGDOSE
Drug dose (for transmitting doses for pharmacokinetics)
FERT
Fertility
HEM/BC
Hematology (coagulation) differential count
H&P.HX.LAB
History for laboratory studies
HL7.CYTOGEN
Clinical cytogenetic report
HL7.GENETICS
Clinical genetic report
HLA
HLA tissue typing antigens and antibodies
HNA
Human neutrophil alloantigens
HPA
HPA typing
LABORDERS
Laboratory order codes
MICRO
Microbiology
MISC
Miscellaneous
MOLPATH
Molecular pathology
MOLPATH.DELDUP
Gene deletions or duplications
MOLPATH.INV
Gene inversion
MOLPATH.MISC
Gene miscellaneous
MOLPATH.MUT
Gene mutation
MOLPATH.NUCREPEAT
Nucleotide repeats
MOLPATH.PHARMG
Pharmacogenomics
MOLPATH.REARRANGE
Gene rearrangement
MOLPATH.TRISOMY
Gene chromosome trisomy
MOLPATH.TRNLOC
Gene translocation
NR STATS
Normal range statistics
PANEL.ABXBACT
Susceptibility order sets
116
PANEL.ALLERGY
Allergy order set
PANEL.BLDBK
Blood bank order set
PANEL.CELLMARK
Cell marker order sets
PANEL.CHAL
Challenge order set
PANEL.CHEM
Chemistry order set
PANEL.COAG
Coagulation order set
PANEL.DRUG/TOX
Drug level & Toxicology order set
PANEL.FERT
Fertility testing order set
PANEL.HEDIS
Healthcare Effectiveness Data and Information Set order set
PANEL.HEM/BC
Hematology & blood count order set
PANEL.HL7.CYTOGEN
HL7 cytogenetics panel
PANEL.HL7.GENETICS
HL7 genetics panel
PANEL.HLA
HLA order set
PANEL.HNA
HNA order set
PANEL.HPA
HPA order set
PANEL.MICRO
Microbiology order set
PANEL.MISC
Miscellaneous order set
PANEL.MOLPATH
Molecular pathology order set
PANEL.OBS
Obstetrics order set
PANEL.PATH
Pathology order set
PANEL.SERO
Serology order set
PANEL.SPEC
Specimen set
PANEL.UA
Urinalysis order set
PATH
Pathology
PATH.PROTOCOLS.BRST
Pathology protocols - breast
PATH.PROTOCOLS.GENER
Pathology protocols - general
PATH.PROTOCOLS.PROST
Pathology protocols - prostate
PATH.PROTOCOLS.SKIN
SPEC
Pathology protocols - skin
Serology (antibodies and most antigens except blood bank and infectious
agents)
Specimen characteristics
UA
Urinalysis
SERO
Table 32c: Attachment Term Classes
Abbreviation
Attachment Term Class
ATTACH
Attachment
ATTACH.AMB
Ambulance attachment
ATTACH.CARD
Cardiac attachment
ATTACH.CLINRPT
Clinical report attachment
ATTACH.CPHS
Children's Preventative Health System attachment
ATTACH.ED
Emergency department attachment
ATTACH.GENERAL
General attachment
ATTACH.GI
Gastrointestinal attachment
ATTACH.LAB
Laboratory attachment
ATTACH.MEDS
Medication attachment
117
ATTACH.MODIFIER
Modifier attachment
ATTACH.OBS
Obstetrics attachment
ATTACH.PERIODONTAL
Periodontal attachment
ATTACH.REHAB
Rehabilitation attachment
ATTACH.REHAB.ABUSE
Alcohol/Substance abuse rehabilitation attachment
ATTACH.REHAB.CARDIAC
Cardiac rehabilitation attachment
ATTACH.REHAB.NURS
Specialized nursing attachment
ATTACH.REHAB.OT
Occupational therapy attachment
ATTACH.REHAB.PSYCH
Psychiatric rehabilitation attachment
ATTACH.REHAB.PT
Physical rehabilitation attachment
ATTACH.REHAB.PULM
Pulmonary rehabilitation attachment
ATTACH.REHAB.RT
Respiratory rehabilitation attachment
ATTACH.REHAB.SOCIAL
Medical social work attachment
ATTACH.REHAB.SPEECH
Speech therapy rehabilitation attachment
ATTACH.RESP
Respiratory attachment
PANEL.ATTACH.MOD
Modifier attachment panel
Table 32d: Survey Term Classes
Abbreviation
Survey Term Class
PANEL.SURVEY.AAOS
American Academy of Orthopaedic Surgeons
PANEL.SURVEY.ADVAULT
ADVault survey set
PANEL.SURVEY.AHRQ
Agency for Healthcare Research and Quality (AHRQ) survey set
PANEL.SURVEY.AMNART
American National Adult Reading Test (AmNART) set
PANEL.SURVEY.AUASI
American Urological Association (AUA) Symptom Index set
PANEL.SURVEY.BIMS
Brief Interview for Mental Health Status (BIMS) set
PANEL.SURVEY.BPI
Brief Pain Inventory (BPI) set
PANEL.SURVEY.CAM
Confusion Assessment Method (CAM) set
PANEL.SURVEY.CARE
Continuity Assessment Record and Evaluation (CARE) set
PANEL.SURVEY.CDC
Centers for Disease Control (CDC) set
PANEL.SURVEY.CMS
Centers for Medicare & Medicaid Services set
PANEL.SURVEY.COOP
Dartmouth Cooperative Functional Status Test (COOP) set
PANEL.SURVEY.EPDS
Edinburgh Postnatal Depression Scale set
PANEL.SURVEY.ESRD
End Stage Renal Disease (ESRD) facility survey set
PANEL.SURVEY.GDS
Geriatric Depression Scale (GDS) set
PANEL.SURVEY.GNHLTH
General Healthy survey set
PANEL.SURVEY.GPCOG
General Practitioner Assessment of Cognition (GPCOG) set
PANEL.SURVEY.HAQ
Health Assessment Questionnaire (HAQ) set
PANEL.SURVEY.HARK
Humiliation, Afraid, Rape, and Kick (HARK) set
PANEL.SURVEY.HHCC
Home Health Care Classification set
PANEL.SURVEY.HHS
Department of Health and Humsn Services set
PANEL.SURVEY.HIV-SSC
Signs and Symptoms checklist for persons living with HIV set
PANEL.SURVEY.howRU
howRU outcomes instrument set
PANEL.SURVEY.LIV-HIV
PANEL.SURVEY.MDS
Living with HIV set
Minimum Data Set for Nursing Home Resident Assessment and Care Screening
set
PANEL.SURVEY.MFS
Morse Fall Scale set
118
PANEL.SURVEY.MTLHLTH
Mental Health survey set
PANEL.SURVEY.NEUR
Neurological survey set
PANEL.SURVEY.NEUROQ
Quality of Life Outcomes in Neurological Disorders (NeuroQol) set
PANEL.SURVEY.NHANES
National Health and Nutrition Examination Survey (NHANES) set
PANEL.SURVEY.NHCS
National Health Care Survey (NHCS) set
PANEL.SURVEY.NMMDS
Nursing Management Minimum Data set
PANEL.SURVEY.NORTON
Norton Scale survey set
PANEL.SURVEY.NSRAS
Neonatal Skin Risk Assessment Scale survey
PANEL.SURVEY.OASIS
Outcome and Assessment Information Survey set
PANEL.SURVEY.OMAHA
PANEL.SURVEY.OPTIMAL
OMAHA survey set
Outpatient Physical Therapy Improvement in Movement a
Assessment Log set
PANEL.SURVEY.PAS
Patient Activity Scale (PAS) set
PANEL.SURVEY.PASII
Patient Activity Scale II (PAS-II) set
PANEL.SURVEY.PCORI
PANEL.SURVEY.PCORNET
Patient-Centered Outcomes Research Institute (PCORI) set
Patient Centered Outcomes Research Network (PCORnet) Common Data
Model (CDM) set
PANEL.SURVEY.PHQ
Patient Health Questionnaire set
PANEL.SURVEY.PROMIS
Patient Reported Outcomes Measurement System set
PANEL.SURVEY.QAM
Quality Audit Marker set
PANEL.SURVEY.QRDA
Quality Health Reporting Document Architecture set
PANEL.SURVEY.RFC
Residual Functional Capacity set
PANEL.SURVEY.SAMHSA
Substance Abuse and Mental Health Services Administration (SAMHSA) set
PANEL.SURVEY.USSGFHT
United States Surgeon General Family Health Tool (USSGFHT) set
PANEL.TIMP
Test of Infant Motor Performance (TIMP) set
PANEL.UPDRS
Unified Parkinson's Disease Rating Scale (UPDRS)
SURVEY.AAOS
American Academy of Orthopaedic Surgeons (AAOS) survey
SURVEY.ADHD
Attention Deficit Hyperactivity Disorder (ADHD)
SURVEY.ADVAULT
ADVault survey
SURVEY.AHRQ
Agency for Healthcare Research and Quality (AHRQ) survey
SURVEY.AMNART
American National Adult Reading Test (AmNART)
SURVEY.AUASI
American Urological Association (AUA) Symptom Index
SURVEY.BPI
Brief Pain Inventory (BPI)
SURVEY.CARE
Continuity Assessment Record and Evaluation (CARE) survey
SURVEY.CDC
Centers for Disease Control (CDC) survey
SURVEY.CERNER
Cerner survey
SURVEY.CMS
Centers for Medicare & Medicaid Services (CMS) survey
SURVEY.COOP
Dartmouth Cooperative Functional Status Test (COOP)
SURVEY.EPDS
Edinburgh Postnatal Depression Scale (EPDS)
SURVEY.ESRD
End Stage Renal Disease (ESRD) facility survey
SURVEY.GDS
Geriatric Depression Scale (GDS) survey
SURVEY.GNHLTH
General Health survey
SURVEY.GOSE
Glasgow Outcome Scale Extended (GOS-E)
SURVEY.GPCOG
General Practitioner Assessment of Cognition (GPCOG)
SURVEY.HAQ
Health Assessment Questionnaire (HAQ)
SURVEY.HARK
Humiliation, Afraid, Rape, and Kick (HARK)
SURVEY.HHS
Department of Health and Human Services (HHS) survey
SURVEY.howRU
howRU outcomes instrument survey
SURVEY.HWS
Healthy Weight Summary (HWS)
119
SURVEY.MDS
Minimum Data Set (MDS) for Nursing Home Resident Assessment and Care
Screening survey
SURVEY.MFS
Morse Fall Scale (MFS) survey
SURVEY.MISC
Miscellaneous survey
SURVEY.MTLHLTH
Mental Health survey
SURVEY.NHANES
National Health and Nutrition Examination Survey (NHANES)
SURVEY.NEURO
Neurological survey
SURVEY.NEUROQ
Quality of Life Outcomes in Neurological Disorders (NeuroQol) survey
SURVEY.NHCS
National Health Care Survey (NHCS)
SURVEY.NIH_TOOLBOX
NIH Toolbox survey
SURVEY.NMMDS
Nursing Management Minimum Data Survey (NMMDS)
SURVEY.NORTON
Norton Scale survey
SURVEY.NSRAS
Neonatal Skin Risk Assessment Scale (NSRAS)
SURVEY.NURSE.HHCC
Home Health Care Classification (HHCC) survey
SURVEY.NURSE.HIV-SSC
Signs and Symptoms Checklist (SSC) for persons living with HIV survey
SURVEY.NURSE.LIV-HIV
Living with HIV survey
SURVEY.NURSE.OMAHA
OMAHA survey
SURVEY.NURSE.QAM
Quality Audit Marker (QAM) survey
SURVEY.OASIS
SURVEY.OPTIMAL
Outcome and Assessment Information Survey (OASIS)
Outpatient Physical Therapy Improvement in Movement and
Assessment Log (OPTIMAL)
SURVEY.PAS
Patient Activity Scale (PAS)
SURVEY.PASII
SURVEY.PCORNET
Patient Activity Scale II (PAS-II)
Patient Centered Outcomes Research Network (PCORnet) Common Data
Model (CDM)
SURVEY.PHQ
Patient Health Questionnaire (PHQ)
SURVEY.PROMIS
Patient Reported Outcomes Measurement System (PROMIS) survey
SURVEY.QRDA
Quality Health Reporting Document Architecture (QRDA) survey
SURVEY.RFC
SURVEY.SAMHSA
Residual Functional Capacity (RFC) survey
Substance Abuse and Mental Health Services Administration (SAMHSA)
survey
SURVEY.USSGFHT
United States Surgeon General Family Health Tool (USSGFHT) survey
TIMP
Test of Infant Motor Performance (TIMP) survey
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Appendix C - Calculating Mod 10 Check Digits
The LOINC code is a numeric code with a Mod 10 check digit. The algorithm for calculating a Mod 10
check digit is as follows:
Instructions
Example
1. Using the number 12345, assign positions to the digits, from right to left.
1st = 5
2nd = 4
3rd = 3
4th = 2
5th = 1
2. Take the odd digit positions counting from the right (1st, 3rd, 5th, etc.)
531
3. Multiply by 2.
1062
4. Take the even digit positions starting from the right (2nd, 4th, etc.).
42
5. Append (4) to the front of the results of (3).
421062
6. Add the digits of (5) together.
4+2+1+0+6+2 = 15
7. Find the next highest multiple of 10.
20
8. Subtract (6) from (7).
Thus, 5 is the Mod 10 check digit for 12345.
20 - 15 = 5.
Calculating the check digit for LOINC Parts, Answers, and other identifiers with characters
We use a variant of the basic Mod 10 algorithm to calculate LOINC parts and answer identifiers because
those identifiers contain the alpha prefixes “LP” and “LA” (which stand for LOINC Part and LOINC
Answer). A detailed description of the method is available here:
https://wiki.openmrs.org/display/docs/Check+Digit+Algorithm
This same method could be used for calculating check digits for user-assigned “X codes” (that contain a
leading “X” character) as well.
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Appendix D - Procedure for Submitting Additions/Changes to
LOINC
Introduction
Since its inception, LOINC has been developed as an open standard. We welcome requests for new terms!
Submissions from LOINC users have helped us grow and adapt quickly. Likewise, we welcome
suggestions for changes to existing terms or other enhancements like additional synonyms or term
descriptions.
Regenstrief balances the desire to respond quickly to new term submissions with the review processes
necessary for a high quality standard. We can only be quick if the requesters provide clear and
comprehensive information about the terms they are submitting. A list of information required for a
submission is provided below.
New requests are often for variations on observations we already have in the database. For example, there
may be an existing term for a particular test result with serum as the specimen (system) and a user
requests an identical term for a specimen of gastric contents. With the supporting information, these kinds
of requests are usually straightforward.
Please check the LOINC website pre-release page, “What’s Coming in the Next Release”, to see if there
is a similar new term prior to submitting your request.
Even when requesters provide complete information with their submission, some requests require
discussion and decision by the LOINC Committee before Regenstrief completes them. These kinds of
requests are for things like:
(1) an entirely novel kind of measurement
(2) use of LOINC codes in ways not previously agreed upon by the LOINC Committee
Before you Submit
Please note that we tend to avoid the use of methods for chemistry tests. We will not routinely accept
requests for method-specific chemistry tests. Only in very special circumstances will we distinguish
among analytic methods in chemistry. We do distinguish microbiology, serology, and coagulation tests by
method type. Even here, however, we do not distinguish every variation in method. Look in the body of
this User’s guide for information about the kinds of distinctions that we make.
Note that our policy is to allow both method-vague (no method) as well as method-specific measures in
serology (measures of Ab and Ag), and in antibiotic susceptibility testing.
Please pay special attention to submissions that include the system of serum or plasma alone. For most
chemical analyses there is no important clinical difference between the values obtained from serum and
those obtained from plasma, and we would like to represent them in the database as Ser/Plas to indicate
our indifference to the distinction. Unfortunately, many requesters of new terms define their request in
terms of the one that they happen to use (e.g., serum or plasma) without telling us that the measure can
really be done on either serum or plasma. Most such requests should be for Ser/Plas as the system
(sample). If the measurement MUST be done on either serum or plasma, please scientifically justify your
122
request and send documentation; otherwise you will greatly delay our response to your submission.
Survey instrument content has some additional complexity. If the instrument is copyrighted by a third
party, Regenstrief will need to obtain permission prior to being able to model it in LOINC. In general,
new LOINC terms are required for questions or variables that have different enumerated answer lists.
How to Submit
First things first
The information you provide about your local test/measurement and how it is used is more important
than the proposed LOINC name you come up with. Having complete information on what your local
test is makes the review process much smoother and helps us create clear term definitions as well as
verifying and enhancing other accessory content, which benefits everyone. The kinds of information
we need does vary a bit depending on the type of content (lab, radiology, document titles, survey
questionnaires, etc), so not all items are applicable all of the time.
Format for submissions
We recommend that you send requests using the RELMA generated file. If not RELMA, then you must
use one of the templates available on the LOINC web site:
http://loinc.org/submissions/new-terms
The preferred method for submitting proposed LOINCs is using RELMA’s built-in functionality.
See the section titled “RELMA Submission” below or review the RELMA manual for more details.
Required information
The set of information required for a particular submission depends on the content of the request. In order
for us to process your request, we need:
•
•
•
•
•
•
•
•
•
•
•
•
Local test/observation name
Local order (panel) name
Name of send out lab (if applicable)
Name of healthcare organization that stimulated the request for this term (if you are submitting on
behalf of someone else)
Description of the test
o For laboratory tests and clinical measurements, the description should indicate what is
measured, how it is performed, and how it is used clinically (e.g. what conditions does it
diagnose, monitor, screen for, etc.).
o For other kinds of clinical terms, such as clinical documents, the description should
indicate the expected information content that would be sent as the result value (i.e. what
kinds of information this document or report contains).
Units of measure (for quantitative observations)
Answer lists (for qualitative observations) (both normal and abnormal answers)
Sample results, reports (if applicable)
If the request is for a panel, the request should include the tests that comprise the panel. Whether
or not each test already has a LOINC code should be included, and for any tests that do not
already have a code, all of the above information for each individual test should be provided
Package inserts, test kit documentation (if applicable)
Vendor, instrument, and/or reagent kit used to perform this test (if applicable)
Description of the project or activity that stimulated the request for this term (e.g. IHE
123
•
•
•
Antepartum Record Profile, Indiana Network for Patient Care health information exchange
project, etc.)
Implementation guide (for terms designed for use in the context of a specific messaging
implementation guide)
Original survey form (for questionnaires or survey content)
Any other documentation that may assist us in creating the requested codes
RELMA submission
The RELMA program can aid you in creating submissions by allowing you to create, manage and store
submission terms in a way that is similar to how the program creates, manages and stores local working
sets. With RELMA, you can create terms for submission over time and submit groups of terms in batches.
The program will track when the term was created and the date when you submitted the term. The
program will help you organize the terms that you create and it will automate the process of creating the
submission files.
For detailed instructions on how to use the RELMA propose a term feature, please see Appendix A of the
RELMA manual. You can be downloaded the RELMA Manual here:
http://loinc.org/downloads/files/RELMAManual.pdf.
Excel file submission
If you are not using RELMA for submission, please use one of the templates provided on our website:
http://loinc.org/submissions/new-terms
Other formats (e.g. distributed database fields, exported internal/local formats) will not be accepted.
Sending Submission Files to Regenstrief Institute
Regardless of the file type, please email your submission and related documents to
[email protected].
Within a day or two of receipt of your file, you will receive a confirmation email and the submission
process will be underway. You may receive additional communication from Regenstrief with requests for
further information if required. Once the submission process has completed, you will receive files
containing your requested codes.
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Appendix E - Examples for LOINC Property Matching
1. Content (Cnt). Like concentration except that volume in the denominator is replaced by mass. By
extension:
CCnt
Catalytic Content, catalytic activity of a component per unit mass of a sample (system).
24048-1|Alpha galactosidase:CCnt:Pt:Fib:Qn
MCnt
Mass Content, mass of component per unit mass of a sample (system).
9435-9|Isopropanol:MCnt:Pt:Tiss:Qn
Note: All of the heavy metal measurements in hair, nails, and tissue should all be mass
contents.
8157-0|Arsenic:MCnt:Pt:Nail:Qn
NCnt
Number Content, number of component entities per unit mass of a sample (system).
20771-2|Coliform bacteria:NCnt:Pt:Egg:Qn:Viability count
2. Fraction (FR). Fraction of component A in a group of entities B, C, Y, N in system 1. By extension:
CFr
Catalytic Fraction
2536-1|Lactatedehydrogenase1/Lactatedehydrogenase.total:CFr:Pt:Ser/Plas:Qn:Electrophoresis
9642-0|Creatine Kinase.BB/Creatine kinase.total:CFr:Pt:Ser/Plas:Qn
NFr
Number Fraction
10602-1|Spermatozoa.abnormal head/100 spermatozoa:NFr:Pt:Semen:Qn
764-1|Neutrophils.band form/100 leukocytes:NFr:Pt:Bld:Qn:Manual count
MFr
Mass Fraction
2614-6|Methemoglobin/Hemoglobin.total:MFr:Pt:Bld:Qn
SFr
Substance Fraction
30192-9|Acetylcholine receptor modulation Ab/Acetylcholine Ab.total:SFr:Pt:Ser:Qn
VFr
Volume fraction.
4545-0|Hematocrit:VFr:Pt:Bld:Qn:Spun
3. Ratio (RTO). Ratio of component A to component B in system 1. By extension:
CRto
Catalytic Ratio (previously Catalytic Concentration Ratio, CCRto)
2325-9|Gamma glutamyl transferase/Aspartate aminotransferase:CRto:Pt:Ser/Plas:Qn
SRto
Substance Ratio (previously Substance Concentration Ratio, SCRto)
2958-7|Sodium/Potassium:SRto:Pt:Sweat:Qn
MRto
Mass Ratio (previously Mass Concentration Ratio, MCRto)
2768-0|Phenylalanine/Tyrosine:MRto:Pt:Ser/Plas:Qn
NRto
Number Ratio
11138-5|Myeloid cells/Erythroid cells:NRto:Pt:Bone mar:Qn
VelRto
Velocity Ratio
12022-0|Resistivity index:VelRto:Pt:Uterine artery.right:Qn:Doppler.calculated
VRatRto Volume Rate Ratio
29462-9|Pulmonic flow/Systemic flow:VRatRto:Pt:Circulatory system.XXX:Qn:US.doppler
Ratio
1811-9|Amylase/Creatinine renal clearance:Ratio:24H:Urine:Qn
125
Note:
CSF/Serum Protein calculation is not a ratio, because the measured components are not in the same
system. Its property type is relative mass concentration, RelMCnc (see below).
Note:
If the units of the denominator and numerator are both mass (e.g., mg/g), use MRto
13719-0|Carnitine/Creatinine:MRto:Pt:Urine:Qn
If the units of the denominator and numerator are both substance (e.g., mmol/mol) use SRto
22695-1|Carnitine/Creatinine:SRto:Pt:Urine:Qn
If the units of the denominator and numerator are different (mmol/g), use Ratio
17866-5|Carnitine/Creatinine:Ratio:Pt:Urine:Qn
4. Relative (REL). Relative amount of component A in system 1 compared to system 0. By extension:
REL should be used anywhere an actual measurement is divided by a measurement on a normal or
control. It should also be used when a quotient is created by dividing a measured substance in Serum by
the same substance measured in CSF, Urine, etc.
RelMCnc
Relative Mass Concentration (as noted previously)
2858-9|Protein.CSF/Protein.serum:RelMCnc:Pt:Ser+CSF:Qn
3235-9|Coagulation factor XII Ag actual/Normal:RelMCnc:Pt:PPP:Qn:Imm
RelTime
Relative time
3232-6|Coagulation factor XII activity actual/Normal:RelTime:Pt:PPP:Qn:Coag
RelCCnc
Relative Catalytic Concentration
28660-9|Plasminogen actual/Normal:RelCCnc:Pt:PPP:Qn:Chromo
RelRto
Relative Ratio
1756-6|Albumin.CSF/Albumin.SerPl:RelRto:Pt:Ser/Plas+CSF:Qn
RelVol
Relative Volume
19853-1|Capacity.inspiratory.bs/Capacity.inspiratory.preop:RelVol:Pt:Respiratorysystem:Qn:Spirometry
RelVrat
Relative Volume Rate
20161-6|Voluntaryventilation.max^postbronchodilator/MVV:predicted:RelVRat:Pt:Respiratory system:Qn
5. Cmplx. Other divisions of one measurement by another that are not covered by the above rules should
be classed as having Complex (Cmplx) properties, and the exact formula for deriving the quantity
should be explicitly stated.
6. Arbitrary. Arbitrary concentration of items. If we are not measuring the activity of an enzyme then the
units of measure and properties are:
Possible Values
Units/mL, IU/mL, etc.
Units/gm, IU/gm, etc.
Unit/min, IU/24hr, etc.
Unitless (Patient/Control)
Property
Scale
ACnc
ACnt
ARat
AFr
Qn
Qn
Qn
Qn
126
NOTE: If we are measuring the activity of an enzyme then the units of measure and properties are:
Possible Values
Property
U/mL, Units/mL, etc.
U/gm, Units/gm, etc.
U/24hr, Unit/min, etc.
Unitless (Patient/Control)
Scale
CCnc
CCnt
CRat
CFr
Qn
Qn
Qn
Qn
7. If the property is Titr then the scale is always Qn.
For any X Ab or Ag:
Possible Values
Property
<1:2, 1:4, 1:8...
Scale
Titr
Qn
8. For Any X Ab or Ag:
Possible Values
Property
Scale
Neg, Indeterminate, Pos
1+, 2+, 3+...
<1:2, 1:4, 1:8...
Neg, 1:4, 1:8 ...
Neg, 0.90 …
PrThr
PrThr
Titr
Titr
ACnc
Qn
Qn
Qn
Ord
Ord
(EIA units)
9. For any intensive evaluation whose value comes from a finite set of unranked (independent) coded
items the property will be Prid (or Type) and scale Nom. Prid is used in cases where the value set
includes the option of reporting “none”, “not present”, etc. Type is used in cases where the result
always specifies a value from the finite set. For extensive measures whose value comes from a finite
set of unranked coded items, the property will be the extensive property, and the scale will be Nom.
Intensive Properties
Possible Values (coded)
Organism Identified
E. coli, S. aureus, etc.
ABO Group
A, B, AB, O
Surgery (Dis. Summary) Cholecystectomy, Appendectomy
Extensive Properties
Urine Color
Possible Values (coded)
Amber, straw, etc.
Property
Scale
Prid
Type
Prid
Nom
Nom
Nom
Property
Scale
Type
Nom
10. For any intensive evaluation whose value comes from a finite set of unranked (independent) free text
items (or a paragraph) the property will be Prid, or Find and scale Nar to indicate that the result is free
text narrative. For extensive measures whose value comes from a finite set of unranked text items (or
a paragraph), the property will be the extensive property, and the scale will be Nar.
Intensive Properties
Possible Values (text)
Organism Identified
ABO Group
Surgery (Dis. Summary)
E. coli, S. aureus, etc.
A, B, AB, O
Cholecystectomy
Extensive Properties
Urine Color
Amber, straw, etc.
127
Property
Prid
Type
Prid
Scale
Nar
Nar
Nar
Property
Scale
Type
Nar
11. Imp is used to represent the property when the evaluation is a mental abstraction based on one a
collection of measurements and or data. For example, if several measurements are made relative to
immunoglobin levels in Serum and CSF in a myasthenia gravis panel, and if by examining all of the
evidence a pathologist decided that this pattern of findings represented active disease (which could be
represented as a coded value), the result of the pathologist thought process would be represented as:
Myasthenia Evaluation
No disease, chronic disease
Property
Scale
Imp
Nom
If the pathologist evaluation is reported free text or a paragraph of information, the representation
would be:
Myasthenia Evaluation
No disease, chronic disease
Imp
Nar
12. Methods are only used to distinguish things that are identical in the other five LOINC fields but may
differ because the sensitivity or specificity is different for the given methods.
13. Need to be careful in distinguishing end point detection method from property. For example, if
sodium is measured using an ion specific electrode, the property is not a voltage difference. The
voltage difference is just a method for indirectly measuring the sodium concentration. Concentration
is the real property. Likewise, many antigens and antibodies are now measured using optical density
as the detection method. However, the property we are really measuring is an arbitrary concentration
(ACnc), not the optical density. If it is a ratio of optical densities (as with Gliadin Ab, Parvovirus B19
Ab, etc.) that are compared (patient value divided by a standard control), then the property should be
RelACnc (relative arbitrary concentration).
14. ml/min/1.73sqM (Milliliters per min per 1.73 square meters BSA): Similar to the immediately
preceding item. This result has the same property as if it had units of ml/min/sqM. The property of
this measurement should be called “areic volume rate” (ArVRat).
128
Appendix F – Example Acronyms used in LOINC
Table 33: Example Acronyms used in LOINC
Acronym
Meaning
AC
Abdominal Circumference
ADL
Activities of Daily Living
AE
Anion Exchange protein
AP
Anterio-Posterior
APAD
AnteroPosterior Diameter of the Abdomen
AUT
Automated Ultrasound Testing
B2GP1
Beta 2 Glycoprotein 1
BD
Binocular Distance
BOR
Brachio-Oto-Renal
BPC
Biparietal Circumference
BPD
Biparietal diameter
CD
Cluster of differentiation
CDA
Congenital dyserythropoietic anaemia
CDB
Childhood Disability Benefits
cDNA
complementary DNA
CFst
Cine
Calorie Fast
Civilian Health and Medical Program of the Uniformed
Services
Cinematographic
CMS
Centers for Medicaid and Medicare Services
CNR1
Cannabinoid receptor 1
COC
Commission on Cancer
COPD
Chronic Obstructive Pulmonary Disease
CPT
Current Procedural Terminology
CRL
Crown-Rump Length
CSF
Cerebral spinal fluid
CW
Continuous wave
CyCD22
Cytoplasmic CD22
DBG
Donna Bennett-Goodspeed
DCIS
Ductal carcinoma in situ
DISIDA
Diisopropyliminodiacetic acid
DRG
Diagnostic Related Groups
DTPA
Diethylenetriamine pentaacetate
Dx
Diagnosis
EBV-LMP
Epstein Barr virus – latent membrane protein
ED
Emergency Department
EDD
Estimated Delivery Date
EEG
Electroencephalogram
EFW
Estimated Fetal Weight
EGD
Esophagogastro duodenoscopy
EKG
Electrocardiogram
EMS
Emergency Medical Service(s)
CHAMPUS
129
ENT
Ear, Nose Throat
ERCP
Endoscopic Retrograde Cholangiopancreatography
FL
Femur Length
FLACC
Face Legs Activity Cry Consolability
FNA
Fine Needle Aspirates
FTA
Fetal Trunk Area
GALOP
Gait disorder Autoantibody Late-age Onset Polyneuropathy
GSD
Gestational Sac Diameter
GSL
Gestational Sac Length
HC
Head Circumference
HIV
Human immunodeficiency virus
HIV-SSC
Sign and Symptom Check-List for Persons with HIV Disease
HL
Humerus Length
HLA
Human Leukocyte Antigen
HMPAO
Hexamethylpropyleneamine oxime
HTLV
Human T-cell Lymphotropic Virus
HWL
Height Width Length
ICD
International Classification of Diseases
ICD9
ICD-O
International Classification of Diseases, Ninth Revision
International Classification of Diseases, Ninth Revision,
Clinical Modification
International Classification of Diseases for Oncology
ID
Intradermal
INR
International normalized ratio
IOD
Inter Ocular Distance
KUB
Kidney-Ureter-Bladder
LHON
Leber hereditary optic neuropathy
LOINC
Logical Observation Identifiers Names and Codes
LVOT
Left Ventricular Outflow Tract
LW
Landsteiner-Wiener
LWT
Length Width Thickness
MAA
Microalbumin aggregate albumin
MEMS
Medication Event Monitoring System
MERSTH
Medical Event Reporting System-Total Health System
MIB-1
Mindbomb homolog 1
MIBG
Metaiodobenzylguanidine
MIC
Minimum inhibitory concentration
MLC
Minimum lethal concentration
MLO
Mediolateral oblique
MMA
Macro aggregate albumin
MVV
Maximum Voluntary Ventilation
NAACCR
North American Association of Central Cancer Registries
Ng
Nasogastric
NPI
National Provider Identifier
OFD
Occipital-Frontal Diameter
O-I BPD
Outer to Inner Biparietal Diameter
OmpC
Outer membrane porin of E coli
ICD9-CM
130
O-O BPD
Outer to Outer Biparietal Diameter
O-O TD
Outer to Outer Tympanum Diameter
OOD
Outer Orbital Diameter
PA
Postero-Anterior
PCP
Primary Care Physician
PEG
Polyethylene Glycol
PHQ
Patient Health Questionnaire
PISA
Proximal Isovelocity Surface Area
PSR
Peridontal Screening and Recording
PYP
Pyrophosphate
QAM
Quality Audit Marker
QID
Four times a day
RAST
Radioallergosorbent test
RFC
Residual Functional Capacity
RFLP
Restriction fragment length polymorphism
RUG
Resource Utilization Groups
SAB
Streptoavidin-biotin
SBT
Sequence based typing
SC
Sulphur colloid
SCB
Sertoli cell barrier
SCL
Scleroderma
SEER
Surveillance Epidemiology and End Result
TAD
Transverse Abdominal Diameter
TC
Thoracic Circumference
TCD
Transverse Cerebellar Diameter
TD
Transaxial Diameter
TEC
Tubingen electric campimetry
TID
Three times a day
TNM
TTD
Tumor, node, metastasis
Toxoplasma, Rubella. Cytomegalovirus, Herpes Simplex
Virus
Transverse Thoracic Diameter
TU
Tuberculin Units
VTI
Velocity Time Integral
VWF
von Willebrand Factor
TORCH
131
Appendix G – LOINC Technical Briefs
Technical briefs have been developed for various LOINC terms to clarify either the meaning, current nomenclature, or use case of a given term.
The following technical briefs are included in this manual and linked to related LOINC terms in RELMA.
D-Dimer Revisions in LOINC
Author: J. Gilbert Hill, MD, PhD
Cockcroft-Gault formula for estimating creatinine clearance, Schwartz equation for Glomerular
Filtration Rate and MDRD formulae
Authors: Gilbert Hill, MD, PhD with edits by Clement J McDonald, MD
Inducible Clindamycin Resistance in Staphylococcus and Streptococcus
Author: David Baorto, MD, PhD
KIR Gene Family
Oxygen Saturation and LOINC
Authors: Gilbert Hill, MD, PhD and Clement J McDonald, MD
Nomenclature of Salmonella Species, Subspecies, and Serovars
Segmented Neutrophils versus Polymorphonuclear WBC
Vitamin D Summary
Free Thyroxine Index Variants
132
D-DIMER
2006-11-24
The Problem:
For many years a test known as "D-dimer" has been used for the assessment of patients with
DIC, and more recently, for the exclusion of the diagnosis of DVT or PE. The units used in
expressing results are usually ng/mL or ug/L, so that a report might look like:
D-dimer = nn ug/L
or
D-dimer = nn ng/mL
Occasionally, this expression is modified to read
D-dimer = nn ug/L DDU, (where the DDU stands for D-dimer units)
With time, new test procedures have been developed, in which newer methods of analysis and
of preparation of the test standard have led to the use of new "units" in expressing results.
With these reagent sets, a report might look like:
D-dimer = xx FEU ug/L
or
D-dimer = xx ug FEU/L
or
D-dimer = xx ug/L FEU, (where FEU is an acronym for fibrinogen equivalent units)
The location of FEU in the unit is not consistent: some users place the FEU before the "ug",
some after the "ug", and some after the "L".
From a clinical perspective, the D-dimer test is potentially of greatest value in ruling out DVT
or PE: for results expressed as ng/mL (= ug/L) the exclusion value is generally less than 250;
for results expressed as ng/mL FEU, the exclusion value is less than 500, and these values are
compatible with a rule-of-thumb conversion published by Biomerieux, July 2003:
600 ng/mL FEU = 300 ng/mL D-dimer.
So . . . now we have the use of single name for a test - D-dimer - but with results falling into
two separate families. The difference between the two families is that the results differ by a
factor of approximately two. This has led to a chaotic situation in the lab, and by extension, to
the bedside, a situation in which both laboratory staff and clinicians are confused as to what
"D-dimer" is being measured and reported. The world-wide web has dozens of references to
the problem, and the CAP has commented frequently, with a series of feature articles in CAP
Today (Feb 2000, Jan 2003, April 2005, May 2005, Summer 2005).
In LOINC terms, we have a component representing two different entities, with identical
primary attributes (component, property, scale, system, time aspect and scale), differentiated
only by method and units, both of which are very weak discriminators.
The fundamental problem is the lack of a useful standard. The International Society on
Thrombosis and Haemostasis has had a subcommittee working for more than ten
years on D-dimer standardization, without success, and it is said that a seat on the
133
committee comes with retirement benefits.
The following figures provide an estimate of the scope of the problem: in a 2004 US (CAP)
survey, 59% of labs reported FEU, 41% reported D-DU and 8% did not know the units they
were using; in a 2005 Canadian (QMPLS) survey, 68% of labs reported D-DU, 31% reported
FEU, and 1% did not know the units they were using.
Resolving the Problem
The obvious solution to the problem is to have different names for the two "families" of D
dimer. But what should these names be?
Contributing to the original problem is the unfortunate choice of the acronym FEU, for
fibrinogen equivalent units. The inclusion of the word "unit" gives the impression that FEU is
a unit in the metrological sense, whereas it would be more reasonable to think of it as a unit in
the structural sense - e.g., a unit such as glucose in a larger molecule such as starch.
Given this interpretation, FEU may be more closely related to, or equivalent to the
"component" (in the LOINCian sense), rather than to the metrological unit. In other words,
FEU is the name of what is measured: just as the amount of glucose can be measured in a
sample, so can the amount of FEU.
From this it is logical to propose that existing entries in LOINC retain the component name
FIBRIN D-DIMER, but that a new entry be created with the name FIBRIN D-DIMER.FEU. In
accordance with LOINC naming conventions, a dot (.) separates the analyte name from the
"subspecies". This proposed name protects the connection with the D-dimer family, but
efficiently separates it as a different entity.
The fully specified name would be
FIBRIN D-DIMER.FEU:MCNC:PT:PPP:QN:EIA
There is at least one precedent in LOINC for this type of component modification - see
LOINC 4539-3, Erythrocyte Sedimentation Rate.Zeta.
The quantitative D-dimer entries in LOINC 2.17 are as follows:
134
D-dimer results from American Proficiency Institute 2004 Testing Program
These tables hint at some of the problems associated with the measurement of Ddimer, in particular the inaccuracy and imprecision, but also proved a convenient
example of the problem under discussion: Biomerieux pioneered the use of the
acronym FEU, but Biomerieux results are shown in the first, ug/L table, rather than
the second, ug FEU/mL table.
135
136
Cockcroft-Gault formula for estimating creatinine clearance, Schwartz equation
for Glomerular Filtration Rate and MDRD formulae
Authors: Gilbert Hill, MD, PhD with edits by Clement J McDonald, MD
Written: 11/20/2007
1 Estimating creatinine clearance from serum creatinine
1.1 Cockcroft-Gault – not adjusted for body surface area (BSA)
The Cockcroft-Gault formula is used to estimate creatinine clearance from age, weight and serum
creatinine. The original paper from these two authors was Prediction of Creatinine Clearance from
Serum Creatinine, Nephron 1976;16:31- 41 hence the name. Note that Creatinine clearance is a proxy
for Glomerular Filtration Rate (GFR) and some clinical settings describe this as an estimated GFR
(see below).
The basic formula without normalization for BSA is represented in the LOINC data base by the
following term.
35591-7
Creatinine renal
clearance.predicted
VRat
Pt
Ser/Plas
Qn
Cockcroft-Gault
formula
And the formula is as follows
The equation as shown requires weight to be recorded in kg and creatinine in mg/dL, and is valid for
male patients. If the patient is female, the result should be multiplied by 0.85.
Web calculator for creatinine in mg/dL
If the patient’s weight is recorded in kg and the creatinine is reported in umol/L then
results from the above equation must be multiplied by 1.23 for men and 1.04 in women.
Web calculator for creatinine in umol/L
From http://www.sydpath.stvincents.com.au/other/CalcsCrClCGumol.htm
1.2 Cockcroft-Gault – adjusted for body surface area
It is now common practice for the creatinine clearance calculated by the Cockcroft-Gault formula to
be normalized for a body surface area of 1.73 m2.
137
In particular, the Cockcroft-Gault BSA adjusted formula is used by many pharmacy departments
for medication dosage adjustments.
LOINC terms for BSA adjusted creatinine clearance
35592-5
Creatinine renal clearance/1.73
sq M.predicted
VRat
Pt
Ser/Plas
Qn
50380-5
sq M.predicted.female
VRat
24H
Ser/Plas
Qn
50381-3
sq M.predicted.male
VRat
24H
Ser/Plas
Qn
Cockcroft-Gault
formula, corrected
for BSA
Cockcroft-Gault
formula, corrected
for BSA
Cockcroft-Gault
formula, corrected
for BSA
2 Direct prediction of GFR
2.1 Creatinine-based prediction of GFR
2.1.1 Schwartz formula for Pediatrics
The Schwartz formula is used to predict GFR in pediatrics. The original paper by G F Schwartz et al,
is A Simple Estimate of GFR in Children Using Body Length and Plasma Creatinine, Pediatrics
1976;58:259-263 has become more relevant in the last few years because the MDRD formula (below)
is specifically stated NOT to be applicable to patients under 18 years of age. The Schwartz formula
depends on age, sex, and body height and serum creatinine. The equation can be stated as follows:
GFR Calculator for Children
Schwartz Formula
GFR (mL/min/1.73 m2) = k (Height) / Serum Creatinine
k = Constant
o k = 0.33 in Preemie Infants
o k = 0.45 in Term infants to 1 year old
o k = 0.55 in Children to 13 years
o k = 0.65 in Adolescent males (Not females because of the presumed
increase in male muscle mass. The constant remains .55 for females.)
Height in cm
Serum Creatinine in mg/dl
Web calculator for Schwartz Formula
LOINC term for Schwartz formula
50384-7
Glomerular filtration rate/1.73 sq
M.predicted
VRat
24H
138
Ser/Plas
Qn
Creatinine-based
formula (Schwartz)
2.1.2
MDRD 4 variables
The MDRD 4 variable equation is the principle equation recommended by professional nephrology
societies to estimate the GFR. It depends upon serum creatinine, age, sex and race. It also includes a
BSA adjustment term of 1.73 - the average body surface area in an adult male. (Equations
incorporating height and weight can be used to correct this equation when patients are far from the
mean in BSA- but are not routinely used.
The following is (taken from NKF MDR web site )
The National Kidney Disease Education Program (NKDEP) of the National Institute of
Diabetes and Diseases of the Kidney (NIDDK), National Kidney Foundation (NKF) and
American Society of Nephrology (ASN) recommend estimating GFR from serum creatinine
using the MDRD Study equation. This equation depends upon the serum creatinine age, sex
and race to estimate the GFR and therefore improves upon several of the limitations with the
use of serum creatinine alone. The MDRD Study equation has been rigorously developed and
validated, and is more accurate than measured creatinine clearance from 24-hour urine
collections. The equation is:
GFR = 186 x (PCr)-1.154 x (age)-0.203 x (0.742 if female) x (1.210 if black)
GFR is expressed in ml/min/1.73 m2. , In this equation Pcr serum creatinine must be
expressed in mg/dl, and age in years. (Of course other units can be used if the right side of
the above equation is multiplied by the appropriate constant). (all taken from NKF web site http://www.kidney.org/professionals/KLS/gfr.cfm#2
December 04 2006)
Web calculator for MDRD
The glomerular filtration rate predicted by the MDRD formula may be reported in at least
3 ways:
a) All four variables are known and used in the equation. The result would be race and sex adjusted
creatinine clearance.
b) Only two variables (serum creatinine and age) are used in the equation. In this
circumstance, the report may:
i) include a comment saying – “if patient is black, multiply result by 1.21” and/or
“if patient is female, multiply the result by .742”
or ii) may include two values: N1 if white and N2 if black, and a correction factor for sex: if patient is
female, multiply the result by .742.
LOINC codes for MDRD formula
33914-3
48642-3
48643-1
50044-7
M.predicted
M.predicted.non black
M.predicted.black
Glomerular filtration rate/1.73.
sq M.predicted.female
VRat
Pt
Ser/Plas
Qn
VRat
Pt
Ser/Plas
Qn
VRat
Pt
Ser/Plas
Qn
VRat
Pt
Ser/Plas
Qn
139
Creatinine-based
formula (MDRD)
Creatinine-based
formula (MDRD)
Creatinine-based
formula (MDRD)
Creatinine-based
formula (MDRD)
2.1.3
MDRD 6 variables
A six variable version of the MDRD exists. This one depends on the patient’s serum albumin and
serum urea nitrogen values in addition to the MDRD-4 variables, but is not the preferred equation for
this estimate.
Where PCr=serum creatinine concentration (mg/dl) (alkaline picrate method); SUN=serum urea
nitrogen concentration (mg/dl) (urease method); Alb=serum albumin concentration (g/dl)
(bromocresol green method).
Taken from:
Stoves J,Lindley E,Barnfield M,Burniston T, Newstead C. MDRD equation estimates of glomerular
filtration rate in potential living kidney donors and renal transplant recipients with impaired graft
function.Nephrol Dial Transplant.2002,17: 2036-2037
2.2 Cystatin-based prediction of GFR
Although the MDRD equation, based on the measurement of serum creatinine, is the most widely
used method for estimating GFR, an alternative, based on the measurement of serum cystatin is
claimed to have certain advantages.
Estimating Glomerular Filtration Rate in Kidney Transplantation: A Comparison between Serum
Creatinine and Cystatin C-Based Methods, J Am Soc Nephrol 16: 3763–
3770, 2005
Web calculator for Cystatin-based GFR
LOINC code for GFR predicted by a cystatin-based formula
50210-4
M.predicted
VRat
Pt
140
Ser/Plas
Qn
Cystatin-based
formula
Inducible Clindamycin Resistance in Staphylococcus and Streptococcus
Written: 5/12/2011
Macrolide-Lincosamide-Streptogramin B (MLSb) Resistance
There is a phenomenon by which the organism can appear to be susceptible to lincosamindes such as
clindamycin when tested in vitro, yet exposure to an appropriate macrolide (such as erythromycin) can
INDUCE resistance to the clindamycin. This mechanism of resistance involves methylation of the 23S
rRNA binding site that is shared by 3 antibiotic classes (macrolides, lincosamides, and group B
streptogramins) and prevents their binding to the site and exerting their effect. This resistance mechanism
is known (for short) as MLSB.
When one of the erm methylases is produced constitutively, the resistance is constitutive and requires no
induction. However, in some cases, the translation of the erm methylase protein is suppressed and is
activated only after the binding of a macrolide antibiotic to upstream sequences, which alters the mRNA
conformation, allowing it to be translated. Once this occurs, active methylase enzyme is produced which
methylates the binding site for all 3 antibiotic classes, potentially preventing the binding of any of these
antibiotic classes and inducing co-resistance. Detection of this resistance pattern can be detected
phenotypically using disc diffusion (Clindamycin.induced [Susceptibility] by Disk diffusion (KB),
42720-3).
The detection of the presence of either the ermA or ermC gene
The methylase enzyme is encoded by one of the erm genes, generally ermA or ermC in staph, ermB in
strep. Finding ermA or ermC similarly indicates the possibility for resistance to both erythromycin and
clindamycin in Staph (either constitutive or inducible for clinda), so reporting both genes has been
combined in some assays to indicate that one of the two has been detected (Bacterial
erythromyin+clindamycin resistance (ermA + ermC) genes [Presence] by Probe & target amplification
method, 62258-9).
141
The KIR Gene Family
Written: 4/17/2011
Clinical Significance
KIR (Killer cell Immunoglobulin-like Receptor) molecules, a novel category of lymphocyte receptors,
are predominantly found on the surface of natural killer (NK) cells. Through their interaction with HLA
class I molecules, they modulate NK cell activity, central to the ability of those cells to distinguish
between healthy cells and those either infected or transformed. The KIR family of molecules
demonstrates extensive diversity at the gene level, stemming from multiple genes as well as multiple
alleles. As a result of this polymorphism, KIR genotype is unlikely to be identical between individuals (in
a sense similar to their molecular ligand, HLA Class I). The relationship between KIR genotype and
disease is beginning to be elucidated, and is likely to interact with HLA. Needless to say it is a growing
area, but there is evidence that which KIR genes are expressed in an individual may be related to
susceptibility to infections (e.g, HCV, HIV), autoimmune diseases, and certain cancers. Importantly, the
success of hematopoietic cell transplantation for some leukemias may be closely tied to KIR type or KIR
compatibility, and be an additional predictor (with HLA).
Nomenclature of KIR genes and alleles
The KIR genes have been classified under the CD nomenclature as a set of CD158 molecules (CD158a,
CD158b, etc.), but the CD names are not commonly used because they do not specifically reflect
structure, function and gene polymorphism. The frequently used KIR gene nomenclature is developed by
the HUGO Genome Nomenclature committee (HGNC). It includes over 15 genes and is based on
molecular structure. They all begin with “KIR”, the next digit is the number of Immunoglobulin-like
domains, next is “D” for domain, next is a description of the cytoplasmic tail, either “L” for long, “S” for
short, or “P” for pseudogenes. The last digit is an integer to distinguish among different KIR genes having
that same structure. (e.g. KIR2DL1, KIR2DL2, etc). Different alleles of a KIR gene are named in a
fashion similar to that of HLA alleles, with an asterisk following the gene name, followed by digits
indicating differences in encoded proteins and non-coding regions.
References:
Marsh S G, Parham P, Dupont B, Geraghty D E, Trowsdale J, Middleton D, Vilches C, Carrington M,
Witt C, Guethlein L A, Shilling H, Garcia C A, Hsu K C, Wain H. Killer-cell immunoglobulin-like
receptor (KIR) nomenclature report, 2002. Immunogenetics 2003; 55(4):220-226. [PMID: 12838378]
Parham P. MHC class I molecules and KIRs in human history, health and survival. Nat Rev Immunol.
2005; 5(3):201-214. [PMID: 15719024]
Carrington M, Norman P. The KIR Gene Cluster. Bethesda (MD): National Center for Biotechnology
Information (US); May 28, 2003. [PMID: NBK10135]
142
Oxygen Saturation and LOINC®
Authors: Gilbert Hill and Clement J. McDonald
Written: 10/19/2007 – Revised: 7/9/2009
(See NCCLS 46-A Blood Gas and pH Analysis and Related Measurements: Approved Guideline.)
1.
Oxygen saturation
The term “oxygen saturation" is often used to refer to two distinctly different quantities, hemoglobin
oxygen saturation (recommended symbol = sO2) and fractional oxyhemoglobin (recommended symbol =
FO2Hb).
2.
NCCLS 46-A defines the two as follows:
2.1
Hemoglobin oxygen saturation
Hemoglobin oxygen saturation = the amount of oxyhemoglobin in blood expressed as a percent of the
total amount of hemoglobin able to bind oxygen (i.e. oxyhemoglobin (O2Hb) + deoxyhemoglobin (HHb).
Note that carboxyhemoglobin (COHb), methemoglobin (MetHb) and Sulfhemoglobin (SulfHb), the socalled dyshemoglobins (dysHb) are unable to bind oxygen, so are not included in the denominator of this
fraction
sO2 = 100 x O2Hb/(O2Hb + HHb)
More important some instruments, e.g. the pulse oximeter- can not pick up the dyshemoglobins. So they
always report sO2
This quantity may be referred to as "oxygen saturation", Terms such as "functional" oxygen saturation
or oxygen saturation of "available" or "active" hemoglobin, but NCCLS should not be used to name this
quantity...
2.2
Fractional oxyhemoglobin
Fractional oxyhemoglobin = the amount of oxyhemoglobin expressed as a percent of the total
hemoglobin (where total Hb = O2Hb + HHb + [COHb + MetHb + SulfHb] taken all together O2Hb HHb
and the three DysHb's represent the total Hb.
FO2Hb = O2Hb/tHb
A key point here is that it takes a more sophisticated machine to measure Fractional Oxyhemoglobin than
sO2.
3.
When there are no dyshemoglobins present (the usual situation), sO2 = FO2Hb
4.
Oxygen saturation obtained by measuring pH and pO2
An “oxygen saturation" can also be obtained by measuring pH and pO2 and substituting the values into an
empirical formula for the oxyhemoglobin dissociation curve (Hill equation). However, this calculated
approach is prone to many kinds of errors and “oximetry” based on differential spectrophotometry is now
the method of choice.
143
5.
Three principal classes of oximetry
There are at least three principal classes of oximetry, commonly known as:
Pulse (or transcutaneous) oximetry (sensor attached to body surface) Hemoximetry (sample of blood
injected into instrument) Co-oximetry. Historically a Co-oximeter measures Carbon monoxide bound
hemoglobin’s and the other two dyshemoglobins and could only be done in the laboratory with an
injected blood sample Today ( 2009) most laboratory blood analyzers measure all three dyshemoglobins
and are really Co-oximeters, but may not be named as such.
A pulse co-oximeter was placed on the market in 2005 this devise reports the both oxyhemoglobin %,
Carbon monoxide %, the Pleth variability index, it also measures each of the dyshemoglobins. So it
provides an accurate fractional oxygen saturation as well as information about CO poisoning.
6.
Instruments used for pulse and hemoximetry
The instruments used for pulse and hemoximetry base results on calculations from readings at two
different wavelengths, which means they do not reflect the presence of any dyshemoglobins, and
therefore the result they produce will be sO2 (LOINC component Oxygen saturation = NCCLS
hemoglobin oxygen saturation).
7.
Instruments used for co-oximetry
The instruments used for co-oximetry base results on calculations from readings at four to eight different
wavelengths, which means they are able to reflect the presence of any
dyshemoglobins, and therefore the result they produce will be FO2Hb (LOINC component
Oxyhemoglobin/Hemoglobin. total = NCCLS fractional oxyhemoglobin).
LOINC will name its components according to the NCCLS recommendation, and apply the
corresponding NCCLS synonyms i.e. sO2 and FO2HB to the components, oxygen saturation and
Hemoglobin Oxygen fraction, respectively and include the defining equation (see above) for the terms
that carry these respective components. We will retain oxygen saturation as a synonym for both sO2 and
FO2Hb so that mappers who may not know the official names will still be able to find the terms.
LOINC will use the property of MFR (mass fraction) to identify the property of these terms.. There
would only be an imperceptible difference between the numerical representation of this quantity as a
MFR versus an SFR (substance or molar fraction), By LOINC convention we use MFR rather than SFR
in such cases.
Depending upon the naming precision of laboratory, it may be difficult to determine whether a result
called an Oxygen saturation is really an sO2 or FO2Hb, The other tests in the panel, and the inclusion of
method names in the test order or battery and the source of the term (clinical laboratory, cardiac cath
laboratory, respiratory therapy, nursing) all provide guidance for the mapping. But it may be necessary to
contact the source to be sure in some cases.
If a battery reports both a fractional oxyhemoglobin and oxygen saturation the situation should be clear. If
the method is co-oximetry or the batter includes a separate measure of Carboxyhemoglobin (or any of the
other dyshemoglobins) then the will be reporting a fractional oxyhemoglobin. If the method is pulse
oximetry- then you have a sO2. Most central and ICU based blood gas measures will produce a fractional
oxyhemoglobin.
144
Finally, in the U.S. these results are almost always reported with units of percent (%), but these results are
reported as pure fractions (E.g. 20% becomes 0.2) in some environments.
145
Nomenclature of Salmonella Species, Subspecies, and Serovars
Written: 7/9/2011
Salmonella nomenclature is complex and has caused confusion. At the present time, by molecular
methods the genus Salmonella is known to have only 2 species: Salmonella enterica and Salmonella
bongori. Salmonella enterica is divided into 6 subspecies, each of which is further divided into numerous
serovars (or serotypes) based on serological testing of somatic(O) and flagellar(H) antigens. Serovars are
then designated by a formulaic concatenation of the antigens, known as the “antigenic formula”. The
terms “serovar” and “serotype” appear to be used interchangeably, however, there has been a preference
expressed for the term “serovar” by the Association of Public Health Laboratories and the World Health
Organization (which uses “serovar” in its documentation). As a result, that will be the term used in this
document.
A significant number of what are now known to be serovars were originally thought to be distinct species
of Salmonella, and those species names became rooted in common clinical usage. As a result, Salmonella
nomenclature deviates from that of other bacteria, which, for the most part, do not have common names
assigned to serovars. (Even the well-known E. coli O157:H7 is known by its antigenic formula.)
Salmonella, on the other hand consists of 2579 individual serovars (2007 WHO documentation), about
1400 of which have common names.
Here is where it gets tricky(er). While it would be impractical to eradicate commonly used names for
important serovars, formatting is used to indicate that the names are not that of species, generally by
NOT italicizing and instead capitalizing the first letter of the serovar name as follows: “Salmonella
enterica subsp. enterica serovar Typhimurium”. Since all the commonly named serovars are in the
subspecies enterica, that middle designation can be left off, resulting in the name “Salmonella enteric
serovar Typhimurium”.
LOINC ® Terms Associated with Salmonella Serotyping:
Salmonella sp identified [Type] in Isolate (59846-6)
This code has one of 7 possible answers to differentiate the 2 species and 6 subspecies in the case of
enterica. When performed by the CDC, the answer is derived from a series of about 50 biochemical tests
and consists of 7 possibilities:
Salmonella enterica subspecies enterica (type I )
Salmonella enterica subspecies salamae(type II )
Salmonella enterica subspecies arizonae(type IIIa )
Salmonella enterica subspecies diarizonae(type IIIb )
Salmonella enterica subspecies houtenae(type IV )
Salmonella bongori
Salmonella enterica subspecies indica(type VI)
Salmonella sp antigenic formula [Identifier] in Isolate by Agglutination (56475-7)
This code has a discrete set of over 2500 possible answers representing the antigenic formula
146
concatenated from the O and H antigens and sometimes other antigens found by agglutination testing.
This code is intended to report only the antigenic formulae of the serovar, not the common name for the
serovar.
The format of the antigenic formula generally is expected to contain the subspecies type (I,II,IIIa, etc),
then followed by somatic (O) antigens, flagellar (H) phase 1 antigens, flagellar (H) phase 2 antigens, and
other antigens separated by a colon. So, a Salmonella type IV (Salmonella enteric subspecies houtenae)
with O antigen 43 and H (phase 1) antigens z36, z38 would be reported as “IV 43:z36,z38:-“.
Salmonella sp serovar [Type] in Isolate (65756-9)
This code is intended to report a final answer for the serovar found, thus has an answer list similar in size
to 56475-7. It will report the common name for the antigenic formula reported by that code (if there is a
common name). If there is no common name, it will report the antigenic formula. In about 90% of cases
the antigenic formula reported by 56475-7 will cleanly map to a serovar to report by this code. In the
remaining 10% of cases, however, serovars can be further distinguished even in the light of identical
antigenic formulas. These distinctions can involve further biochemical testing or sometimes further
antigen testing.
147
Segmented Neutrophils Versus Polymorphonuclear WBC
Written: 4/17/2011
Segmented neutrophils are commonly referred to as polymorphonuclear neutrophils, PMNs, or “polys”.
Therefore, in common usage the term polymorphonuclear leukocyte (or polymorphonuclear WBC) refers
to neutrophils. Caution coding in this area should be applied because there is a usage whereby all
granulocytes, including neutrophils, basophils and eosinophils, can be referred to as polymorphonuclear
cells” due to the variable shape of their nuclei. Basophils can therefore be referred to as
polymorphonuclear basophil (PMB), eosinophils as polymorphonuclear eosinophils (PME), in addition to
neutrophils (polymorphonuclear neutrophil, PMN).
Refer to the following Wikipedia page for more information: http://en.wikipedia.org/wiki/Granulocyte
148
Vitamin D
Written: 2/19/2011
General Summary
Vitamin D is a prohormone that is involved in calcium and phosphate homeostasis, bone formation, and
immune regulation. The determination of vitamin D is complex because it is not a single component, but
has 2 major forms, each of which has several metabolic stages leading to an active end product. Vitamin
D3, also known as cholecalciferol, is the form that occurs naturally in humans and is produced in the skin
of vertebrates from 7-dehydrocholesterol exposed to UV B radiation from the sun. Vitamin D3 can also
be obtained from certain dietary animal products and supplementation. Vitamin D2, also known as
ergocalciferol, is introduced into humans primarily by commercial supplementation. It is produced by UV
irradiation of ergosterol, a substance that occurs in yeast, molds and certain plants.
Despite their distinct origins, both vitamin D2 and D3 share similar chemical structure, metabolic
activation in humans, and presumably bioactivity as well, although the literature suggests that vitamin D2
is biologically inferior. Their structures differ only by a side chain, and the starting forms of both in
humans, cholecalciferol and ergocalciferol, are hormonally inactive. Both undergo hydroxylation to 25hydroxyvitamin D(2 or 3) in the liver, followed by further conversion to the active hormone, 1,25dihydroxyvitamin D(2 or 3) in the kidney (or the placenta during pregnancy). 25-hydroxyvitamin D3 is
also known as calcidiol, while the active form 1,25-dihydroxyvitamin D3 is also known as calcitriol. It is
more difficult to find trivial name forms for the vitamin D2 group, although IUPAC recommends
ercalcitriol for the active form of D2 (See nomenclature table).
“Vitamin D” based Name
Vitamin D2
Vitamin D3
25-Hydroxyvitamin D2
25-Hydroxyvitamin D3
1,25-dihydroxyvitamin D2
1,25-dihydroxyvitamin D3
Trivial Name
ergocalciferol
cholecalciferol
-none foundcalcidiol
ercalcitriol
calcitriol
Measurement of the vitamin D parent compound, whether D3 or D2, has limited clinical value because,
with a half-life of about 1 day, the value reflects mostly recent sun exposure or intake (there may be a
utility in assessing absorption from the gut). Vitamin D status is generally determined by measuring the
intermediate 25-hydroxyvitamin D form, the major circulating form with a half-life of 2-3 weeks.
Whether there is a value to distinguishing the relative contribution of 25-hydroxyvitamin D2 compared to
D3 depends on the objective. Understanding vitamin D status generally requires a total number; however,
the need to assess response to supplementation with vitamin D2, for example, may be helped with distinct
reports on both forms. The active hormone, 1,25-dihydroxyvitamin D (2 or 3), has a short half- life of 4 –
6 hours, and its concentration is tightly regulated. This makes it a poor candidate for assessing nutritional
vitamin D status, although its measurement has utility in differential diagnosis of hyper and hypocalcemia
and bone and mineral disorders.
An alternative metabolism pathway in the kidney yields a 24,25-dihydroxyvitamin D form. This is the
most prevalent dihydroxylated metabolite in circulation, but (unlike the 1,25-dihydroxyvitamin D forms),
it is not hormonally active. The physiological role of 24,25-dihydroxyvitamin D is unclear, although it
149
has been suggested that the active hormone may self-modulate by shunting toward this pathway.
Specific Parts
Vitamin D3
Vitamin D plays important roles in maintaining calcium and phosphate levels, and in immune regulation,
but its determination is complex due to multiple metabolic intermediates and 2 major forms. Vitamin D3,
also known as cholecalciferol, is the parent compound of one of the 2 major families of vitamin D (D2
and D3). Vitamin D3 is the form of vitamin D that is endogenously produced in the skin of vertebrates
(including humans) upon exposure to sunlight (specifically UV B). It can also be obtained from dietary
animal products, or dietary supplements. Vitamin D3, whether produced endogenously or ingested, is a
prohormone form that is not active until further metabolism first to 25-hydroxyvitamin D3 (in the liver),
then finally to 1,25-hydroxyvitamin D3 (in the kidney or placenta) . Measurement of the vitamin D parent
compound, whether D3 or D2, has limited clinical value because, with a half-life of about 1 day, the value
reflects mostly recent sun exposure or intake (there may be a utility in assessing absorption from the gut).
Vitamin D status is generally determined by measuring the intermediate 25-hydroxyvitamin D form, the
major circulating form with a half-life of 2-3 weeks. The need to assess response to supplementation with
vitamin D2, for example, may be helped with distinct reports on both forms.
Vitamin D2
Vitamin D plays important roles in maintaining calcium and phosphate levels, and in immune regulation,
but its determination is complex due to multiple metabolic intermediates and 2 major forms. Vitamin D2,
also known as ergocalciferol, is the parent compound of one of the 2 major families of vitamin D (D2 and
D3). Vitamin D2 is the form of vitamin D that is not endogenously produced in the skin. It is produced
upon UV radiation of ergosterol, which occurs in molds, yeast, and certain plants, and its major
introduction into humans is via commercial supplementation. Vitamin D2 is a prohormone form that is
not active until further metabolism first to 25-hydroxyvitamin D2 (in the liver), then finally to 1,25hydroxyvitamin D2 (in the kidney or placenta) . Measurement of the vitamin D parent compound,
whether D3 or D2, has limited clinical value because, with a half-life of about 1 day, the value reflects
mostly recent sun exposure or intake (there may be a utility in assessing absorption from the gut).
Vitamin D status is generally determined by measuring the intermediate 25-hydroxyvitamin D form, the
major circulating form with a half-life of 2-3 weeks. The need to assess response to supplementation with
vitamin D2, for example, may be helped with distinct reports on both forms.
25-Hydroxyvitamin D, 25-Hydroxyvitamin D2, and 25-Hydroxyvitamin D3
The 25-hydroxyvitamin D intermediate is the major circulating metabolite of vitamin D with a half-life of
2-3 weeks, and it is the most useful measure of vitamin D status. The determination of vitamin D is
complex due to multiple metabolic intermediates and 2 major forms, vitamin D2 and D3. The lack of
specification of the form generally indicates that both are included. Vitamin D3 is the form of vitamin D
that is endogenously produced in the skin of vertebrates (including humans) upon exposure to sunlight
(specifically UV B), whereas vitamin D2 is produced upon UV radiation of ergosterol, which occurs in
molds, yeast, and certain plants, and its major introduction into humans is via commercial
supplementation, although both D3 and D2 can be included as supplements. The 25-hydroxyvitamin D
metabolites of both forms (also known as calcidiol in the case of D3) are produced in the liver from the
corresponding parent compound. Whether there is a value to distinguishing the relative contribution of
150
25-hydroxyvitamin D2 compared to D3 depends on the objective. Understanding vitamin D status
generally requires a total number; however, the need to assess response to supplementation with vitamin
D2, for example, and other specific cases, may be helped with a distinct reports on both forms.
1,25-Hydroxyvitamin D, 1, 25-Hydroxyvitamin D2, and 1, 25-Hydroxyvitamin D3
1,25-hydroxyvitamin D is the physiologically active form of vitamin D. When metabolically activated to
this form, vitamin D plays important roles in maintaining calcium and phosphate levels, and in immune
regulation. It increases intestinal absorption of calcium and phosphorus, and in concert with parathyroid
hormone increases bone resorption. There are 2 major forms of vitamin D, each of which can be activated
to a 1,25-dihydroxy form (also known as calcitriol in the case of D3 and ercalcitriol in the case of D2).
Vitamin D3 is the form of vitamin D that is endogenously produced in the skin of vertebrates (including
humans) upon exposure to sunlight (specifically UV B). It can also be obtained from dietary animal
products, or dietary supplements. Vitamin D2 is the form of vitamin D that is not endogenously produced
in the skin. It is produced upon UV radiation of ergosterol, which occurs in molds, yeast, and certain
plants, and its major introduction into humans is via commercial supplementation. Vitamin D, whether
produced endogenously or ingested, is a prohormone form that is not active until further metabolism first
to 25 hydroxyvitamin D3 (in the liver), then finally to the active 1,25 hydroxyvitamin D3 (in the kidney
or placenta). The active hormone, 1,25-dihydroxyvitamin D (2 or 3), has a short half-life of 4 – 6 hours,
and its concentration is tightly regulated. This makes it a poor candidate for assessing nutritional vitamin
D status, although its measurement has utility in differential diagnosis of hyper and hypocalcemia and
bone and mineral disorders.
24,25-Dihydroxyvitamin D3
24,25-dihydroxyvitamin D3 is a compound which is closely related to 1,25-dihydroxyvitamin D3, the
active form of vitamin D3, but (like vitamin D3 itself and 25-hydroxyvitamin D3) is inactive as a
hormone. It is produced from 25-hydroxyvitamin D3 by alternative metabolic pathway in the kidney. The
physiological role of 24,25-dihydroxyvitamin D is unclear, although it has been suggested that the active
hormone may self-modulate by shunting toward this pathway.
References:
Houghton, L A, Vieth R. The case against ergocalciferol (vitamin D2) as a vitamin supplement. American Journal of
Clinical Nutrition 2006; 84 (4):694-697. [PMID: 17023693]
Morris, H A. Vitamin D: A Hormone for All Seasons - How much is enough? Understanding the New Pressures.
Clinical Biochemist Reviews 2005; 26(1):21-32. [PMID: 16278774]
St-Arnaugh, R, Glorieux, F H. 24, 25-Dihydroxyvitamin D—Active Metabolite or Inactive Catabolite?
Endocrinology 1998;139:3371-3374. [PMID: 9681484]
IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN). Nomenclature of vitamin D.
Recommendations 1981. Pure & Appl.Chem. 1982; 54(8): 1511—1516.
Burtis, C A, Ashwood, E R. Tietz Textbook of Clinical Chemistry, 3rd ed.: Saunders; 1994.
Wikipedia: http://en.wikipedia.org/wiki/Vitamin_D
151
Free Thyroxine Index Variants
Written: January 2012
Although direct measurement of the free hormones has recently become more prevalent, the older
methods to estimate free hormone levels by deriving an index still persist. The index methods involve
adjusting the total thyroid hormone concentration (TT4) for the thyroid binding capacity of the serum (T3
uptake or thyroid binding globulin TBG) to yield an indicator or estimate of the free hormone level, free
thyroxine index (FTI). Over time and across labs this calculation has been and is done in different ways,
yielding different results sometimes with different properties. This is mostly due to distinctions in what is
known as “T uptake”. Here are some variations:
1) FTI = TT4(ug/ml) x T3 uptake (%)/100
• This has sometimes been noted leaving off the division by 100, but not in practice: FTI =
TT4(ug/ml) x T3 uptake(%).
2) FTI = TT4(ug/ml) x (T3 uptake patient/T3 uptake control) (ratio)
• Here, “T3 uptake” used in the calculation is actually the thyroid hormone binding ratio
noted throughout the literature (THBR), the ratio of patient to reference serum values of
T3 uptake.
3) FTI = TT4(ug/ml) / T uptake units (ratio)
• Here “T uptake units” is ratio of patient to reference serum levels of thyroxine binding
globulin (TBG).
Notes:
• In variation 1, the uptake is a %, while in variations 2 and 3 the uptake is a unit-less ratio
normalized to control, known in the literature as the thyroid hormone binding ratio (THBR).
• Variation 1 is apparently the reporting approach used by Mayo, ARUP, and LabCorp and many
hospital labs (such as one large NY hospital). It adjusts the total T4 by a T3 uptake %
(approximate range 25-40%), and yields FTI values often in the approximate range of 1 to 5
(adults) and is reported as unit-less.
• Variation 2 is apparently the reporting approach used by Quest Diagnostics-Nichols and some
hospital labs (such as another large NY hospital), and variation 3 apparently the primary method
used by Abbott Axsym (although values can be converted).
• Variations 2 and 3 both adjust the total T4 (TT4) by a ratio referenced to a control value of 1, so
FTI numerically is in the approximate range of TT4 concentration 5 – 12 (adults). While it is
usually reported as unit-less, there is a case that it is really an adjusted TT4 concentration, and in
fact the Abbott AxSym package insert (variation 3 above) notes units of ug/dl for its calculated
FTI value.
• THBR is a normalized T3 uptake which represents how much labeled T3 did NOT find a binding
site in patient serum, meaning it is the INVERSE of available binding sites. Conversely, in the
AxSYM method “T uptake units” is a control normalized ratio of TBG, a measure proportional to
the binding sites. This may account for why one MULTIPLIES and the other DIVIDES by the
152
•
ratio. The TBG is not the only thyroid hormone binding protein, another distinction between 2
and 3.
Historically T3 instead of T4 has been more commonly used as the tracer in uptake assays for
practical reasons. T3 has a lower affinity for TBG, so more would be available to be taken up by
the scavenger and easier to count. With non-isotopic techniques, this may be less of an issue, and
it has been suggested that T4 uptake would be more appropriate to adjust TT4 concentration. T4
uptake assays do exist.
153
Appendix H - LOINC Committee Members
Name
Organization
Location
Ray Aller
John Baenziger
Suzanne Bakken
Pam Banning
James Barthel
Dean Bidgood
Bruce Bray
James Campbell
Jim Case
Jim Cimino
Lorie Carey
Robert Dolin
James K Fleming
Arden Forrey
Bill Francis
Pavla Frazier
Bruce Goldberg
Alan Golichowski
Barry Gordon
Brian Griffin
Gil Hill
Stan Huff
Cindy Johns
William (Bill) Karitis
Ted Klein
Jeff Lamothe
Lee Min Lau
Diane Leland
Pat Maloney
Doug Martin
Susan Matney
Ken McCaslin
Clem McDonald
University Southern California Pathology
Indiana University Hospital
Columbia School of Nursing
3M
H. Lee Moffitt Cancer Center
Duke Medical Center
University of Utah
University of Nebraska
California Veterinary Diag Labs
Columbia Presbyterian Med Center
Canada Health Infoway
Mayo Foundation
Laboratory Corp of America
University of Washington
Augilent Technologies
University of Utah
Kaiser Permanente
Indiana Univ. Dept. of Medicine
C/NET Solutions
Quest Diagnostics
Hospital for Sick Children
Intermountain Health Care
LabCorp
Department of Defense, U.S. Navy
Klein Consulting, Inc
USAF
3M HIS
Riley Hospital for Children
Quest Diagnostics
Regenstrief Institute/IUSOM
3M HIS
Quest Diagnostics
NLM Lister Hill National Center for
Biomedical Communications
Regenstrief Institute
National Medical Services Association
Vanderbilt University
Centers for Disease Control
Oregon Health Sciences University
Parners Healthcare, Inc.
Instituto Tecnologie Biomediche
Mayo Medical Laboratories
Clinical Architecture
World Health Organization
CDC
Eli Lilly & Co.
University Hospital
Health Patterns, LLC
Regenstrief Institute/IUSOM
ARUP Laboratories
New York State Office of Mental Health
CDC
3M HIS
Vista, CA
Indianapolis, IN
New York, NY
West Linn, OR
Tampa, FL
Durham, NC
Salt Lake City, UT
Omaha, NE
Davis, CA
New York, NY
Saskatoon, SK, Canada
Rochester, MN
Burlington, NC
Seattle, WA
Andover, MA
Salt Lake City, UT
Pasadena,CA
Indianapolis, IN
Berkeley, CA
Rutherford, NJ
Toronto, ON, Canada
Salt Lake City, UT
Burlington, NC
Onley, MD
Ridge, NY
Biloxi, MS
Salt Lake City, UT
Indianapolis, IN
Teterboro, NJ
Indianapolis, IN
Salt Lake City, UT
Collegeville, PA
Bethesda, MD
Kathy Mercer
Deirdre O’Neill
Judy Ozbolt
Dan Pollock
Rick Press
Christine Raine
Angelo Rossi Mori
Jon Rosenblatt
Shaun Shakib
John Stelling
Steve Steindel
Jeff Suico
Anders Thurin
Wayne Tracy
Daniel Vreeman
Larry West
Thomas White
Warren Williams
Pat Wilson
154
Indianapolis, IN
Willow Grove, PA
Nashville, TN
Atlanta, GA
Portland, OR
Brookline, MA
Rome, Italy
Rochester, MN
Salt Lake City, UT
Geneva, Switzerland
Atlanta, GA
Indianapolis, IN
Linkoping, Sweden
Overland Park, KS
Indianapolis, IN
Salt Lake City, UT
New York, NY
Atlanta, GA
Salt Lake City, UT
Annex - RadLex-LOINC Radiology
Playbook User Guide
Welcome to the RadLex-LOINC Radiology Playbook User Guide. This work is the result of a multi-year
collaboration between Regenstrief Institute and the Radiological Society of North America (RSNA),
supported by the National Institute of Biomedical Imaging and Bioengineering (NIBIB). The
participants have developed a model that combines and unifies the useful aspects of LOINC Radiology
and the RSNA RadLex Playbook. Both of these terminology initiatives are designed to represent
concepts of radiology orderables and results and their attributes.
Each term in the unified Playbook model has a name (a.k.a. description), and takes on a number of
attributes. This guide is intended to describe the semantics, syntax, and proper usage of those
attributes. Within the terminology, these attributes are used as building blocks to construct several
types of standard names, including a fully specified name, long name, and short name.
A list of the Playbook attributes is shown below. Attributes are organized according to attribute
groups, consisting of the major bullet headings below, and by more specific sub-attributes, shown in
the minor bullets below and denoted by a dot after the attribute group, such as Pharmaceutical.Route.
•
•
•
•
•
•
•
Modality
o Modality.Subtype
Anatomic Location
o Anatomic Location.Region Imaged
o Anatomic Location.Imaging Focus
o Anatomic Location.Laterality.Presence
o Anatomic Location.Laterality
View
o View.Aggregation
o View.View type
o View.View type.Maneuver
Pharmaceutical
o Pharmaceutical.Substance Given
o Pharmaceutical.Route
o Pharmaceutical.Timing
Reason for Exam
Guidance
o Guidance for.Presence
o Guidance for.Approach
o Guidance for.Action
o Guidance for.Object
Subject
The chapters that follow provide a guide to the usage of each of the above attributes.
1
RadLex-LOINC Harmonized User Guide
June 28, 2016
Codes and workflows
Radiology procedure codes impact a variety of workflows in the health care enterprise, including
ordering, scheduling, billing, protocol specification, image acquisition, and image interpretation,
among others. In each case, the codes serve specific purposes in identifying imaging exams. While
there is a great deal of overlap between these workflows, there are also important differences. For
example, radiology billing is often concerned with a less detailed description of an imaging exam, while
the radiology ordering process often involves more information about the requested study.
The Playbook work has been primarily focused on addressing the needs of the radiology ordering
workflow. The semantic model described in this document is intended principally to characterize
radiology “orderables.” This then raises the question of what constitutes an orderable exam, an issue
which is complicated by at least two factors. First, different institutions may expose different levels of
granularity at the point of radiology order entry. While one may consider “CT abdomen / pelvis with
contrast” to be an appropriate option in an order entry system, another institution may wish to provide
the choice “CT abdomen / pelvis with contrast, liver mass.” Second, in certain circumstances, what is
actually done to satisfy an imaging request may not match the ordered procedure precisely. For
example, image-guided interventions often entail procedural modifications at the time of the exam. In
such cases, modified or additional orderables may be entered, even though these may not have been
exposed in the clinical ordering interface.
The model aims to allow for this type of variation, so as to broadly fulfill the needs of radiology ordering
workflows at a variety of institutions. Note that related work, at a more granular level addressing the
technical factors in image acquisition, is being done by the DICOM Standards Committee [1].
2
June 28, 2016
1 CONTENTS
2
SYNTAX............................................................................................................................ 5
2.1
OPERATORS ...................................................................................................................................................5
2.1.1
2.1.2
2.1.3
2.1.4
2.1.5
2.1.6
2.2
3
4
“.” ............................................................................................................................................................................. 5
“+” ............................................................................................................................................................................ 5
“>” ............................................................................................................................................................................ 5
“&”............................................................................................................................................................................ 5
“&or” ........................................................................................................................................................................ 5
Precedence .............................................................................................................................................................. 5
PARALLELISM.................................................................................................................................................5
MODALITY .............................................................................................................................................. 6
3.1
DEFINITIONS ..................................................................................................................................................6
3.2
USAGE NOTES................................................................................................................................................6
3.3
ALLOWED MODALITY/SUBTYPE COMBINATIONS ..............................................................................................7
ANATOMIC LOCATION ............................................................................................................................. 9
4.1
DEFINITIONS ..................................................................................................................................................9
4.2
SYNTAX AND MODELING PRINCIPLES ............................................................................................................ 10
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.2.7
4.2.8
4.2.9
4.2.10
4.2.11
4.2.12
4.2.13
4.2.14
5
6
Specifying region(s) imaged without an imaging focus..................................................................................... 10
Imaging foci that cross body regions .................................................................................................................. 10
Specifying multiple anatomic locations .............................................................................................................. 10
Broad region combined with a specific focus...................................................................................................... 11
Specifying terms without an anatomic location ................................................................................................ 11
Operator precedence ............................................................................................................................................ 11
Parallelism ............................................................................................................................................................. 11
Region imaged as grouper +/- coarse-grained descriptor .................................................................................. 11
Laterality ............................................................................................................................................................... 12
Subject .............................................................................................................................................................. 12
Ectopic Anatomy .............................................................................................................................................. 12
Anatomic terminology in the extremities ...................................................................................................... 12
Singular vs. Plural ............................................................................................................................................ 13
Singular vs. Plural in the context of Vasculature ........................................................................................... 13
VIEW .................................................................................................................................................... 14
5.1
DEFINITIONS ................................................................................................................................................ 14
5.2
USAGE NOTES.............................................................................................................................................. 14
5.3
EXAMPLES ................................................................................................................................................... 15
PHARMACEUTICAL ................................................................................................................................ 17
6.1
DEFINITIONS ................................................................................................................................................ 17
6.2
SYNTAX ....................................................................................................................................................... 17
6.3
EXAMPLES ................................................................................................................................................... 17
6.4
SPECIFYING MORE THAN ONE PHARMACEUTICAL ............................................................................................ 17
3
June 28, 2016
6.5
USAGE NOTES.............................................................................................................................................. 18
6.5.1
6.5.2
6.5.3
6.5.4
6.5.5
6.6
Preference for Generic Names ............................................................................................................................. 18
Route...................................................................................................................................................................... 18
Intra versus Via ...................................................................................................................................................... 18
Existence versus Absence .................................................................................................................................... 18
Relationship to View.Maneuver sub-attribute ................................................................................................... 18
ISSUES ......................................................................................................................................................... 19
REASON FOR EXAM .............................................................................................................................. 20
7
7.1
DEFINITIONS ................................................................................................................................................ 20
7.2
EXAMPLES ................................................................................................................................................... 21
7.3
NOTES ......................................................................................................................................................... 21
8
GUIDANCE ............................................................................................................................................ 22
8.1
DEFINITIONS ................................................................................................................................................ 22
8.2
USAGE NOTES.............................................................................................................................................. 22
8.2.1
8.2.2
8.2.3
8.2.4
8.2.5
8.3
9
Guidance for.Approach......................................................................................................................................... 22
Guidance for.Action .............................................................................................................................................. 22
Anatomic Location and Guidance for.Object ..................................................................................................... 23
Modality attribute................................................................................................................................................. 23
Specifying more than one procedure .................................................................................................................. 23
EXAMPLES ................................................................................................................................................... 24
SUBJECT ............................................................................................................................................... 25
9.1
10
DEFINITIONS ................................................................................................................................................ 25
REFERENCES..................................................................................................................................... 26
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June 28, 2016
2 SYNTAX
2.1 OPERATORS
The model uses several logical operators (“.”, “+”, “>”, “&”, “&or”) to express combinations of atoms.
2.1.1
“.”
Used to specify refinement of a given attribute or attribute component. For example, the dot operator
may be used with the View type component of the View attribute to specify a Maneuver sub-component
(e.g. “lateral.flexion”). For modality subtypes, it is used to indicate a certain type of imaging technique
(e.g. “CT.angio”).
2.1.2
“+”
Used to combine atoms, such as Anatomy atoms or View atoms, with AND semantics.
2.1.3
“>”
Used exclusively to separate the body region from the anatomic imaging focus.
2.1.4
“&”
Used to separate atoms for parallelism, such as in Anatomy or View. May alternatively be used as a
low-precedence AND, such as in the Pharmaceutical.Timing attribute WO&W, which has a combined
“before and after” notation. This is the lowest-precedence of all the operators in the model.
2.1.5
“&or”
Used to join two atoms via logical (inclusive) disjunction. For example, fine needle aspiration &or core
needle biopsy means that either or both procedures were done.
2.1.6
Precedence
Operator precedence, from greatest to least is as follows: “.”, “+”, “>”, “&”, “&or”
2.2 PARALLELISM
In selected circumstances, it is necessary to specify multiple values for two or more specific attributes or
components. In such cases, the correspondences between values across attributes or components may
be modeled by maintaining a consistent ordering of values. For example, a radiographic exam of the
ribs often includes a radiograph of the chest. The specific views may include an AP view of the chest,
and an oblique view of the ribs. Multiplicity of the Anatomic Location attribute as well as the View
attribute is modeled using parallelism and the “&” operator. That is, with Anatomic Location “Chest &
Ribs” and View “AP & Oblique” the appropriate correspondence between “Chest” and “AP” as well as
between “Ribs” and “Oblique” is maintained by virtue of the relative positions of the atoms (i.e. both
“Chest” and “AP” are listed first in their respective attributes).
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June 28, 2016
3 MODALITY
3.1 DEFINITIONS
Modality is used to represent the device used to acquire imaging information. Modalities consist
predominantly of a subset of the two-letter DICOM modality codes. DICOM modality codes are listed in
PS3.3, Section C.7.3.1.1.1 in the 2016 release of the DICOM standard [2]. In addition, the modality code
“RP” is used to indicate image-guided procedures for which the specific type of imaging is not explicitly
modeled.
A Modality subtype may be listed, separated by a “.”, to signify a particularly common or evocative
configuration of the modality.
Note that when such modality subtypes are specified, the given type of technique is included in a study,
although this does not necessarily imply that the study consists exclusively of that subtype of imaging.
For example, an exam with modality and subtype US.doppler does not mean than only Doppler
imaging was performed. On the other hand, XR.portable generally does indicate that only portable
images were obtained.
3.2 USAGE NOTES
1. Subtype angio. This subtype is used for procedures designed to give angiographic images of
the vessels. This should not be used for US; Doppler should be used instead. Angio is not a
synonym for contrast administration because some angiographic MR studies do not require
intravenous contrast administration.
2. Subtype full field digital and analog for MG. MG.analog indicates an analog mammogram.
MG.full field digital signifies a digital mammogram only. MG without a subtype signifies a
procedure that can be done with digital or analog equipment.
3. CR (computed radiography) vs DX (digital radiography) vs RG (radiographic
imaging/conventional film screen): XR will be adopted generically to signify orders for planar
radiography. When the images are acquired, the imaging modality may wish to insert a more
specific modality code in the DICOM files.
4. Doppler subtype vs DICOM modality codes DD (duplex Doppler) and CD (color flow Doppler).
US.Doppler will be used as the attribute of the orderable procedure. When the images are
acquired, the imaging modality may wish to insert a more specific modality code in the DICOM
files.
5. Portable indicates whether the device is movable or whether the patient will come to the
radiology department for imaging.
6. The SPECT modality will be represented as a subtype of the NM modality (NM.SPECT) rather
than using ST, the DICOM modality code for SPECT.
7. Because there is no DICOM modality code for DEXA, DXA will be adopted as the modality code.
8. When an imaging study involves more than one imaging modality, “+” is used to concatenate
the two modalities, such as “PT+CT” or “NM.SPECT+CT”. The modality listed first corresponds
to the departmental area where the device is typically located. E.g. PT+CT, not CT+PT
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June 28, 2016
9. For studies with two modalities that have separate attributes and are performed consecutively
(e.g., RF Upper GI with XR abdomen), “&” is used in the value of each attribute, including
Modality, to maintain parallelism across attributes.
10. Precedence of operators is “.”, “+”, “&” (“>” is not used in the Modality attribute)
11. The perfusion modality subtype indicates the study is intended to measure tissue perfusion; if
the study is designed to image the vessels, use the angio modality subtype.
12. 3D is an image processing step, and can be performed on images from a variety of modalities.
Its use is discouraged. If adopted locally, it may be used as shown in the Chapter on Reason for
Exam.
13. Modality RP (radiology procedure) is used to refer to image-guided procedures, where the
particular type of imaging used is not specified in the orderable. For example, liver biopsies
may be performed under ultrasound or CT guidance, although the particular modality used may
be at the discretion of the operator. In such cases, RP indicates image guidance not further
specified.
3.3 ALLOWED MODALITY/SUBTYPE COMBINATIONS
•
•
•
•
•
•
•
•
CT
o
o
o
o
o
DXA
o
MG
o
o
o
o
MR
o
o
o
NM
o
o
PT
o
RF
o
o
o
US
o
CT.angio
CT.scanogram
CT.densitometry
CT.perfusion
CT.portable
DXA.densitometry
MG.full field digital
MG.analog
MG.tomosynthesis
MG.stereotactic
MR.angio
MR.functional
MR.spectroscopy
NM.dosimetry
NM.SPECT
PT.perfusion
RF.angio
RF.video
RF.portable
US.densitometry
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June 28, 2016
•
•
o
o
US.Doppler
US.portable
o
o
XR.tomography
XR.portable
XR
RP
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June 28, 2016
4 ANATOMIC LOCATION
This chapter describes how anatomic terms are used to identify the body region and anatomic focus of
imaging. It also specifies the syntax to be used when more than one anatomy term applies to a given
exam code, and delineates how laterality should be specified when necessary.
Please note: as of the June 2016 LOINC release (v2.56), most of the Region imaged and Imaging focus
values have been specified in the LOINC System part (which corresponds to the Playbook Anatomic
Location attribute) according to the syntax described below with two major exceptions. First, the Upper
Extremity and Lower Extremity Regions imaged have not yet been explicitly modeled for most of the
extremity terms that have a specific Imaging focus. Second, the syntax for specifying multiple
Anatomic Locations as described in Section 4.2.3 and 4.2.4 is not yet implemented. We anticipate that
both of these exceptions will be addressed in the December 2016 LOINC release.
4.1 DEFINITIONS
The Anatomic Location attribute specifies the body part or body region that is imaged and includes the
sub-attributes, Region imaged and Imaging focus. The most specific anatomic structure should be
specified. Multiple Anatomic Locations may be specified using the syntax specified below and should be
specified only when necessary to distinguish the code from other codes. Anatomic Location terms are
generally drawn from the RadLex anatomic hierarchy.
Region imaged is used in two ways. First, as a coarse-grained descriptor of the area imaged and a
grouper for finding related imaging exams. Or it is used just as a grouper. For example, when an
abdominal CT focuses on the liver, it images the abdomen as a whole and also would be a relevant
comparison for other abdominal CT exams (e.g. renal CT), thus making abdomen a coarse-grained
descriptor as well as a grouper. Similarly, a head CT focusing on the brain may also be a relevant
comparison for other head CT exams (e.g. orbit CT), making it both a descriptor and grouper.
Alternatively, for most studies with upper extremity or lower extremity as the Region imaged and a
specific Imaging focus, such as wrist or knee, the Region imaged is a grouper only, because the entire
extremity is typically not imaged.
Imaging focus is defined as a more fine-grained descriptor of the specific target structure of an imaging
exam. In many areas, the focus should be a specific organ. For example, in the Region imaged
abdomen, the Imaging focus might be liver, pancreas, adrenal glands, kidneys, etc. In other areas, the
Imaging focus will simply be a more specific area within a given region. For example, in the Region
imaged upper extremity, the Imaging focus might be shoulder, upper arm, elbow, forearm, wrist, hand,
etc.
Our goals are to populate both the Region imaged and Imaging focus sub-attributes for all terms, except
where the Region imaged is the focus of the study (see 4.2.1). We will also constrain Region imaged to
the following short list of regions: head, neck, chest, breast, abdomen, pelvis, upper extremity, lower
extremity.
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June 28, 2016
Exceptions to the short list of Regions imaged include cases in which the Imaging focus exists
throughout the body and is being imaged in its entirety, such as bones or bone marrow. In these cases,
the Region imaged is whole body, e.g. Whole body>Bone marrow. In contrast, when the Imaging focus
exists in multiple parts of the body but only one specific instance is being imaged, the Region imaged is
unspecified, which is given as “XXX” in LOINC, e.g. XXX>Bone.
Pathologic entities may not serve as an anatomic location (e.g. renal tumor). If there is a need to
specify a pathologic entity to distinguish to exam codes, the pathologic entity should be specified with
the Reason for Exam attribute or Guidance for.Object sub-attribute.
4.2 SYNTAX AND MODELING PRINCIPLES
The syntax used to describe the Anatomic Location attribute is as follows:
<body region imaged> “>” <imaging focus>
For example, for an abdominal CT with a focus on the liver, the Anatomic Location would be specified
as:
Abdomen>Liver
As noted in the introduction to this chapter, the June 2016 LOINC release does not reflect this syntax
for most of the existing terms that would be expected to have Upper extremity or Lower extremity as
the Region imaged. For example, the Anatomic Location for wrist is still represented as Wrist rather than
Upper extremity>Wrist.
4.2.1
Specifying region(s) imaged without an imaging focus
If there is a single anatomic context associated with a code, it should be specified as <body region
imaged> without an <imaging focus>, for example, for an abdominal CT, the Anatomic Location
would be specified as:
Abdomen
When multiple regions are imaged without an imaging focus, such as CT of the head and neck, the two
regions are separated by a “+”:
Head+Neck
4.2.2
Imaging foci that cross body regions
Certain imaging foci cross multiple body regions, such as Pharynx, which is included in both the Head
and Neck imaging regions. In this case, the regions will be separated by a “+” as follows:
Head+Neck>Pharynx
4.2.3
Specifying multiple anatomic locations
When more than one anatomic location is imaged, where each location has a different Region imaged
and Imaging focus pair, they are separated by an “&” according to the syntax:
<body region imaged A> “>” <imaging focus A> “&” <body region imaged B>
“>” <imaging focus B>
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June 28, 2016
For example, a study of the chest and abdomen focused on the lung and liver would be specified as
follows:
Chest>Lung & Abdomen>Liver
Note – this is a change from the previous version of Playbook and will be implemented in LOINC
starting with the December 2016 release. The June 2016 release contains terms modeled according to
the previous model, where multiple locations were specified by grouping the Regions imaged together,
separated by a “+”, and grouping the Imaging foci together, also separated by a “+”, with the Regions
imaged and Imaging foci groups separated by “>”. So the example above in the previous model (and
current LOINC release) is specified as:
Chest+Abdomen>Lung+Liver
4.2.4
Broad region combined with a specific focus
In other situations, a specific Imaging focus in one Region imaged may be imaged at the same time as a
different Region imaged without a focus. Consider an MRI examination of the face and neck. Face is an
Imaging focus of the Region imaged head. Neck is an additional Region imaged. In such situations, the
lower precedence of the “&” compared to the “>” operator is used to combine these areas as follows:
Head>Face & Neck
4.2.5
Specifying terms without an anatomic location
In some cases, such as fluoroscopic guidance codes, a specific Anatomic Location may not be relevant,
in which case we use the general unspecified Region imaged.
4.2.6
Operator precedence
The precedence of operators is “.”, “+”,“>”,”&”. For example:
Head+Neck > Pharynx
is equivalent to
(Head+Neck)> Pharynx
4.2.7
Parallelism
In rare instances, a complex study may require parallelism to model correctly. In this instance, an
ampersand is used to separate the elements of the study. For example, a study that consists of a PA
and lateral views of the chest plus 4 oblique views of the right ribs could be represented as follows:
XR Chest&Ribs.Right 2 views & 4 views including PA+Lateral & Right oblique
4.2.8
Region imaged as grouper +/- coarse-grained descriptor
The nature of the study should make it clear whether the Region imaged is functioning as both a coarsegrained descriptor of the area imaged and a grouper or as a grouper only. Following are additional
guidelines to help users make that determination:
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June 28, 2016
1. In general, when the Region imaged is the head, neck, chest, abdomen or pelvis, it is both a coarsegrained descriptor and a grouper;
2. For spine studies, the Region imaged is typically a grouper only (this is an exception to rule #1). For
example, a C-spine exam will have the Anatomic location specified as Neck>Spine.cervical, but typically
the exam would focus on the spine and not include general imaging of the neck;
3. When the Region imaged is upper extremity or lower extremity, it typically functions as a grouper
only.
4.2.9
Laterality
Many exams require laterality to be specified in order to be performed. These exams will be signified
with an Anatomic Location.Laterality.Presence attribute set to True. For terms with Laterality.Presence =
True, the Laterality attribute must not be null. Valid values of the Laterality attribute are:
• Left
• Right
• Bilateral
• Unilateral
• Unspecified
The recommended practice is to specify one of Left, Right, or Bilateral for Anatomic Location.Laterality
whenever Anatomic Location.Laterality.Presence = True. If the Laterality.Presence attribute is False, the
Laterality attribute must be null. Laterality applies to the most specific anatomic part associated with
the exam code.
4.2.10 Subject
Some exams are relevant only to a Fetus or a Gestation. This distinction will be represented when
necessary by the Subject attribute.
4.2.11 Ectopic Anatomy
Ectopic anatomy, such as a transplanted kidney, if needed to distinguish an exam code, should be
specified as a Reason for Exam, not as an Anatomic Location. Anatomic Location corresponds to where
the transplanted kidney is located, e.g., Pelvis.
4.2.12 Anatomic terminology in the extremities
In the upper extremity, the term “upper arm” is preferred over the term “arm.” Even though these are
technically equivalent, the redundancy of “upper arm” provides for greater clarity. “Upper arm” is also
preferred over “humerus” for this area, as the latter is bone-specific and could be construed as
excluding soft tissues. Similarly, in the lower extremity, “lower leg” is preferred over “leg,” “calf” and
“tibia / fibula.”
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June 28, 2016
4.2.13 Singular vs. Plural
The singular form of an anatomic structure is typically used, except in a few specific cases that primarily
apply to vasculature, as noted below.
4.2.14 Singular vs. Plural in the context of Vasculature
For the set of vessels associated with a particular region, organ or a specific group of vessels, we use the
plural “Vessels”, “Veins” and “Arteries” to mean “set of”, for example, “Adrenal vessels” or “Cerebral
arteries.” One use case for such pre-coordination is angiography, for example, CT angiography of the
renal vessels would have the following Anatomic location:
Abdomen >Renal vessels
The plural form does not imply laterality, which is still specified using the laterality attribute (see
4.1.10). For example, “Abdomen>Renal vessels.right” means the set of renal vessels supplying the right
kidney.
Specific named vessels use the singular form, e.g., “Femoral vein” and “Superior mesenteric artery.”
When vessels in an extremity are imaged for a specific reason, such as varicose vein treatment, and
there are different CPT codes for treatment of a single vessel and treatment of multiple vessels, we use
the plural form to mean multiple and also created a singular form to represent treatment of a single
vessel even though that vessel is not named, i.e., “extremity veins” and “extremity vein.”
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June 28, 2016
5 VIEW
5.1 DEFINITIONS
The View attribute is used to indicate the orientation of the patient in the image. This may reflect a
combination of patient position and x-ray beam direction, or may alternatively be captured in a named,
or eponymous, view. While this most commonly refers to radiography (e.g. a lateral radiograph of the
chest), it may also be used with other modalities (e.g. prone CT of the chest).
In many instances, the View attribute will not be specified at all (e.g. MRI of the brain) in the Playbook
model. However, note that in the LOINC model, the Component part of all radiology terms specifies the
type of image acquired based on the modality: “Views” for XR, MAM, and NM, and “Multisection” for
MR, CT, US, NM.SPECT, PT, and XR.tomography.
When View is specified in Playbook, three optional components may be used:
<Aggregation>
<View type>.<Manuever>
The Aggregation component is used to describe the extent of the imaging performed, whether in
quantitative terms (e.g. “3 or more views”) or subjective terms (e.g. “complete”). The use of “Followup” as a value of the aggregation attribute is replaced by the value “Limited.”
View type is used to name specific views, such as “lateral” or “prone.” View type may optionally have an
additional Maneuver sub-component. Maneuver is used to indicate an action taken with the goal of
elucidating or testing a dynamic aspect of the anatomy. For example, flexion and extension views of
the cervical spine are used to detect instability as indicated by changes in spinal alignment. Similarly,
inspiratory and expiratory views of the chest may be used to detect changes in lung volume. Maneuvers
imply an element of patient exertion, and may occur in pairs (e.g. “flexion” and “extension”). These
factors distinguish maneuvers from patient actions used purely to gain a desired perspective. For
example, the cross-table lateral radiograph of the hip requires the patient to be lying supine with the
contralateral leg bent and raised, though the purpose of this is to obtain a lateral angle on the hip rather
than to test stability or dynamic change. In such cases, the patient position is embodied in the named
view type (e.g. “Danelius Miller”) rather than with a maneuver.
5.2 USAGE NOTES
1. Views may be aggregated in groups. Sometimes these groups may be further specified by
naming specific views (e.g. “PA + lateral”), in which case the semantics are that the group
includes the named views. In some cases the views are specified numerically (e.g. “4 views”).
Other times the constituent views of a group may be unspecified (e.g. “complete”).
2. The naming of specific views is optional.
3. The use of an aggregation term is optional.
4. Eponymous views imply patient position and beam direction, as well as anatomic focus.
Anatomic focus will continue to be specified separately as described above, recognizing this
redundancy.
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June 28, 2016
5. Maneuvers may be specified on a per-view basis (e.g. “Lateral.flexion + Lateral.extension”).
6. If no maneuver is specified, it is assumed that the patient is at rest.
7. Laterality may optionally be specified in certain views (e.g. “Lateral,” “Right lateral” or “Left
lateral”). The laterality specified in this case indicates patient position relative to the beam, not
the side of the patient being imaged, and is thus independent of the Anatomic
Location.Laterality sub-attribute.
8. Portable is specified as a Modality subtype instead of a View.
9. The large majority of exams will have no view specified at all. In the RSNA Core Playbook, 29
exams use views out of 1031 exams, and all of these are XR exams.
10. When the number of views is specified for a bilateral exam, the number refers to the number of
views per side (e.g., XR Knee Bilateral 2 Views specifies 2 views of each knee)
11. Time-related factors, such as “48 hours post”, are modeled with the Pharmaceutical attribute.
12. Sometimes, parallelism is required to show which attributes are associated with which views.
The ampersand is used to show parallelism. For example, a combined exam with chest and rib
views would be modeled as:
XR Chest&Ribs.Right 2 views & 4 views including PA+Lateral & Right oblique
That is, the atoms “Chest” “2 views” and “PA+Lateral” form one group, and the atoms
“Ribs.Right” “4 views” and “Right oblique” form another group. Note that this parallelism relies
on a consistent ordering of atoms to maintain proper groupings.
13. If the views for the second anatomic location are unspecified, the unspecified views will be
modeled as “XXX”. For example:
XR&RF Chest&Diaphragm 2 views & XXX
XR&RF Abdomen&UGI Tract 1 view & XXX
5.3 EXAMPLES
<View(s)>
XR
Chest
PA
XR
Chest
L decubitus
CT
Chest
CT
Chest
Supine
XR
Hand, bilateral
Ball catcher
XR
Abdomen
AP
<Aggregation> including <View(s)>
XR
Chest
2 views
{PA + Lateral}
XR
Ankle
Complete
XR
Shoulder
3 views
{Axillary}
XR
Hip
2 views
{Cross table lateral}
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XR
C-spine
4 views
{Right oblique +
Left oblique}
XR
Abdomen
2 views
{Supine + Upright}
XR
C-spine
4 views
{Lateral.flexion +
Lateral.extension}
XR
Foot
3 views
{Lateral.weight-bearing}
XR
Knee.Bilat
4 views
{Right oblique +
Left oblique}
CT
Chest
2 views
{Supine.inspiration +
Supine.expiration}
CT
Colon
2 views
{Supine + Prone}
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6 PHARMACEUTICAL
6.1 DEFINITIONS
The Pharmaceutical attribute specifies the presence or absence of chemical agents relevant to the
imaging procedure. We use this attribute to specify administered contrast agents,
radiopharmaceuticals, medications, or other clinically important agents and challenges during the
imaging procedure.
6.2 SYNTAX
The syntax used to describe the Pharmaceutical attribute specifies several optional components:
<timing/existence><substance given><route>
Only the components required for specifying the pharmaceutical at a clinically important level are
included in the attribute value.
The <timing/existence> attribute can be either simultaneous:
•
•
WO
W
A combined “before and after” notation that denotes separate sets of images:
•
WO & W
Or describing an image taken at a specified time after administration of the pharmaceutical:
•
48H post
6.3 EXAMPLES
Using this syntax, a common contrast specification of without then with IV contrast would be denoted:
WO & W contrast IV
In other cases, the time delay is a key component:
48H post contrast PO
6.4 SPECIFYING MORE THAN ONE PHARMACEUTICAL
The syntax above can also be used to specify more than one pharmaceutical that may be influence the
imaged physiology. For example, a nuclear medicine cardiac stress test may involve administration of a
radiopharmaceutical and a stress agent such as Adenosine, Dobutamine, or Regadenoson. The
attribute value list will contain only single pharmaceuticals. We specify multiple instances of the
pharmaceutical attribute by combining them with “+”:
W adenosine + W radionuclide IV
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June 28, 2016
W dipyridamole + W Tc-99m Sestamibi
6.5 USAGE NOTES
Some pharmaceuticals will be more fully specified than others. For example, some may specify the
specific substance:
W Tc-99m Sestamibi IV
whereas others name a more generic class:
W radionuclide IV
W anesthesia
6.5.1
Preference for Generic Names
We use the generic name of a pharmaceutical, not the brand name, e.g. Tc-99m Sestamibi, not
Cardiolite. We will usually include the brand or trade names as synonyms. In rare cases, we use the
brand name when a generic form does not exist (e.g., Theraspheres).
6.5.2 Route
Where possible, we denote the route of administration by abbreviations for medication routes (Table 6
of the LOINC Users’ Guide). An oral route of administration would be denoted by “PO,” an intravenous
route by “IV.”
6.5.3 Intra versus Via
When describing administration of contrast into specific spaces for which abbreviations do not exist,
the space is spelled out in full, and preceded by “intra” or “via” according to these guidelines.
We use “intra” when the contrast injected goes directly into this anatomic space, and this space is what
is visualized in the study. For example:
W contrast intra lymphatic
We use “via” when the contrast injected goes through this device (e.g., catheter) and into the anatomic
space being visualized. For example:
W contrast via colostomy
6.5.4
Existence versus Absence
The <existence> component of the pharmaceutical attribute allows specification of whether or not the
imaging occurs in the presence of the agent where existence is denoted W, WO, or WO & W. The
existence of WO & W denotes separate images, without and with the pharmaceutical.
6.5.5
Relationship to View.Maneuver sub-attribute
Like the physical maneuvers described in the chapter on the View attribute, pharmaceutical agents are
also intended to test a dynamic aspect of the anatomy, with similarities in how these are modeled. In
some cases, an exam may use one or the other that are intended to produce a similar anatomic
response (e.g., W exercise or W adenosine). Where needed, they can also be used together as different
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June 28, 2016
attributes of the overall term model. For example, in defecography, both a maneuver and contrast are
specified:
W contrast PR & during defecation
6.6 ISSUES
•
•
•
•
•
•
•
•
[Decision: YES] LOINC to change order (WO then W) pattern
[Decision: NO] Should the existence convention be changed to the more redundant but more
clear full expression:
o WO contrast IV & W contrast IV
[Decision: No] Should the combination pharmaceuticals be items in the attribute value list?
Is there a more up to date specification of Routes? Not really. FHIR uses this same table. Some
were added in 2.3.1
[Decision: YES] Should we remove the amount sub-attribute?
Intra articular -> IS (Intrasynovial)
We will use quotes for keeping together separate words within an attribute. We’ll look for
naming conventions to eliminate the need for this. We will convert WO & W to WO&W.
Include the Modifiers from Views:
o Deprecate usage of “1 phase” in LOINC (it is implied unless stated as 3 phase)
o 3 Phase
o 30M post
o 45M post
o Delayed
o Runoff
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7 REASON FOR EXAM
7.1 DEFINITIONS
Reason for exam is used to describe a clinical indication or a purpose for the study. This may refer to a
patient diagnosis, a clinical indication, a clinical status (e.g. “post op”), an intended measurement,
altered anatomy (e.g. “endograft”), or some other indicator of the purpose of the exam (e.g.
“screening”).
The terms “diagnostic” and “screening” are used as values of the Reason for exam attribute, and these
are potentially confusing for two reasons. First, “diagnostic” is often thought of as complementary to
“screening,” in which case the terms refer to the patient’s clinical status (i.e. asymptomatic patients
undergo “screening” exams, whereas symptomatic patients undergo “diagnostic” exams). However,
“diagnostic” is also frequently used in the context of mammography, in which case it is an indicator of
the views to be obtained (specifically, that additional non-standard views may be performed), not an
indicator of the patient’s symptom status. In both cases, “diagnostic” refers to an exam being
performed for the purpose of further work-up. Here we have chosen to model these terms as part of
the Reason for exam semantics, rather than the View semantics.
Second, the question of screening and diagnostic exams “for what” may be another source of
confusion. Here, we take the position that the answer is typically understood: Screening
mammography screens for breast cancer; screening colonography screens for colon cancer. Further,
note that the use of the terms “diagnostic” and “screening” is intended to be limited to those exams
where these are needed to distinguish from some other type of study.
We also use the Reason for exam attribute to distinguish studies that are primarily done in the pediatric
domain. For example, the codes for bilateral hip ultrasound and cranial ultrasound both have the
Reason for exam specified as “for pediatrics”.
We do not create separate codes with pediatrics as the Reason for exam in cases where the same study
is commonly done in both the adult and pediatric population. For example, “Head CT” will be used for
both pediatric and adult studies.
Also note that “3D post processing” is included here as a value of the Reason for exam attribute. This
refers to image rendering done after image acquisition. Some facilities bill for such renderings, which
may be used for surgical planning or other purposes. As a result, these renderings (at least sometimes)
constitute an end-product of the exam, and we have thereby chosen to model such processing as a
reason for performing the exam. While 3D post processing may also be used simply as a diagnostic tool
in image interpretation (and thus not technically a reason for performing the study), we have elected to
simply model any description of 3D post processing here.
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June 28, 2016
7.2 EXAMPLES
<Reason(s)>
XR
Eye
Foreign body
MG
Breast
Diagnostic
MG
Breast
Diagnostic + Call back
US
Pregnancy + Less than 14 weeks
US
Multiple gestation + Greater than 14 weeks
NM
Stomach
Liquid gastric emptying
CT
Heart
Calcium score
7.3 NOTES
1.
2.
3.
4.
10/17/14: Values removed - “mass,” “obstruction,” “patency,” “pre op”
10/17/14: Values added – “intra op,” “endograft”
10/17/14: “Twin pregnancy” replaced with “multiple gestation.”
“Call back” is only to be used in relation to mammography.
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8 GUIDANCE
8.1 DEFINITIONS
The Guidance attribute is used to describe image-guided interventions. Such procedures may range
from the very general (e.g. “CT guided needle placement”) to the very specific (e.g. “fluoroscopy guided
lumbar vertebroplasty, with bone biopsy, additional level”). Some procedures may also be ambiguous
(e.g. “image guided fine needle aspiration and/or core biopsy”).
Imaging guidance for procedures is modeled with three sub-attributes:
<Approach>
<Action>
<Object>
Approach refers to the primary route of access used, such as percutaneous, transcatheter, or
transhepatic. Action indicates the intervention performed, such as biopsy, aspiration, or ablation.
Object is used to specify the target of the action, such as mass, abscess or cyst. For complex
procedures, operators may be used to combine instances of the Guidance attribute.
8.2 USAGE NOTES
8.2.1
Guidance for.Approach
The approach sub-attribute will generally be included in the formal code specification. For some
procedures like needle biopsy, the percutaneous route is the “default” and often assumed route. Local
procedure names will often not include the word “percutaneous” in the name. For purposes of
modeling, we will include percutaneous in the attribute specification. But, to avoid extraneous “clutter”,
the display name for the pre-coordinated term will only include the approach if we have two variants,
one with percutaneous and one with some other route.
In some cases, “percutaneous” may be part of the overall route used for a procedure (e.g.
“percutaneous transhepatic”). In such cases, the primary, or most evocative, route will be used (e.g.
“transhepatic”).
8.2.2
Guidance for.Action
The action sub-attribute will generally be required to adequately specify an image-guided procedure.
Examples include: placement of; replacement/exchange of; removal of; repositioning of; retrieval of;
infusion of; injection of; localization of; check of.
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June 28, 2016
8.2.3
Anatomic Location and Guidance for.Object
For a given procedure, the body region or organ of interest is specified outside of the Guidance
attribute, using the Anatomic Location attribute. On the other hand, when there is a specific site of
pathology targeted by an intervention, this is modeled using the Guidance for.Object sub-attribute. The
expectation is that when normal anatomic specifiers such as “liver” or “abdomen” are used, these are
modeled using Anatomic Location. When a site of disease such as “mass” or “abscess” is described, this
is modeled using Guidance for.Object. Alternatively, the object of a procedure may be a device (e.g.
“central venous catheter”).
Note that the object sub-attribute is optional. Some procedures will not specify a particular pathologic
lesion (e.g. “CT guided liver biopsy”) whereas others will (e.g. “CT guided liver mass biopsy”). In some
cases, neither Anatomic Location nor Guidance for.Object will be specified (e.g. “US guided fine needle
aspiration”).
8.2.4
Modality attribute
The Guidance attribute will generally be used in conjunction with the Modality attribute. Recall that the
modality code “RP” is used for image-guided procedures where the particular imaging modality is not
specified (e.g. “image guided liver biopsy”).
8.2.5
Specifying more than one procedure
Although uncommon, the syntax above can also be used to specify more than one procedure by
repeating the triplet of sub-attributes.
As defined in the Syntax section (2.1), use of “+” to join two procedures means logical conjunction (i.e.
both procedures were done). Use of “&or” to join two procedures means logical (inclusive) disjunction
(i.e. either or both procedures were done).
For example:
Guidance for fine needle aspiration &or core needle biopsy
This term illustrates how the more generic concept of a “needle biopsy” (including both aspiration and
core needle) could be represented. Both procedures in the pair could use whichever sub-attributes of
the triplet were appropriate.
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June 28, 2016
8.3 EXAMPLES
<Anatomic Loc>
<Approach>
<Action>
CT
Liver
Percutaneous
Core biopsy
CT
Liver
Percutaneous
Core biopsy
Mass
RP
Percutaneous
Placement
Drain
RP
Percutaneous
Drainage
Abscess
Transhepatic
Placement
Drain
US
Percutaneous
Placement
Non-tunneled CVC
RP
Percutaneous
Fine needle aspiration
&or Core needle biopsy
RP
Gallbladder
<Object>
US
Pleural space
Percutaneous
Drainage
US
Thyroid
Percutaneous
Fine needle aspiration
Percutaneous
Exchange
RP
Gastrojejunal
tube
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June 28, 2016
9 SUBJECT
9.1 DEFINITIONS
The Subject attribute is intended for use when there is a need to distinguish between the patient
associated with an imaging study, and the target of the study. This situation may occur for pregnant
patients undergoing prenatal imaging exams. The potential for multiple gestation further motivates
the need for the Subject attribute, as an exam may be targeted at a particular one of multiple fetuses.
The Subject attribute may also be used in cases of surgical specimens, such as specimen radiographs at
lumpectomy.
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June 28, 2016
10 REFERENCES
1. http://dicom.nema.org/Dicom/News/oct2013/docs_oct2013/sup121_pc.pdf, Accessed 14 May
2016.
2. http://dicom.nema.org/medical/dicom/current/output/pdf/part03.pdf, Accessed 14 May 2016.
26
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